As the gavel drops to begin the Republican National Convention here on Monday, the party will be focused on two goals: reintroducing Donald Trump as someone the country could imagine in the Oval Office during dangerous times, and healing the leftover wounds of a brutal primary season.

“The convention’s coming at a good time for us to turn the page,” a hopeful Reince Priebus, the party’s chairman, said in an interview after spending the pre-convention week snuffing out a “Never Trump” revolt among a rebellious group of party rulemakers.

Republicans descended on Cleveland, a city tense with security concerns and fears that street protests could turn into riots, as Trump on Saturday brought a chaotic and sometimes surreal vice-presidential selection process to its formal conclusion.

Officially introducing an uncharacteristically conventional running mate, Trump appeared in New York with Indiana Gov. Mike Pence for the first time as a ticket — an event that is normally one of the most intricately choreographed in any presidential campaign.

But Trump did it on a badly lit stage in a rambling speech that was mostly about himself, proving once again that he is a candidate who cannot be scripted.

Here are some of the people who are speaking at the 2016 Republican National Convention in Cleveland and some who've opted to skip the event. (Sarah Parnass,Danielle Kunitz/The Washington Post)

While Trump called Pence “a man who I truly think will be outstanding in every way,” he also acknowledged that one of his reasons for picking him was “party unity, I have to be honest. So many people have said party unity, because I’m an outsider.”

Trump will formally accept the party’s presidential nomination here on Thursday facing big hurdles in the race against Democratic nominee-in-waiting Hillary Clinton. He is behind in most polls, both in battleground states and nationally, even though Clinton has had a difficult few weeks of renewed focus on the controversy over her private email server.

Polls also show Trump with the highest negative ratings of any major-party nominee in recent history, though Clinton herself fares nearly as badly.

Modern conventions are political infomercials, and the four-day gathering in Cleveland will aim to present Trump as a more substantive and compassionate figure than the bombastic, impulsive showman who vanquished 16 rivals to claim the nomination. The incendiary rhetoric that his supporters see as truth-telling has alienated crucial swaths of the general electorate, especially women and minorities.

“He is a likable person,” Priebus said of a candidate to whom he now speaks at least twice a day. “I think as people get to see the person that some of us have gotten to know, that’s going to help him in the general election, because I think people actually want to like him. They’re intrigued by him. They’re interested in him. And him becoming likable will make him unstoppable.”

To that end, the convention producers plan to showcase the celebrity billionaire’s family. His wife, Melania, a Slovenia-born former fashion model who rarely speaks publicly on her husband’s behalf, will deliver prime-time remarks, as will Trump’s four oldest children from his first two marriages, Donald Jr., Ivanka, Eric and Tiffany.

Kayla Epstein explains what the heck is going on at the 2016 RNC. (Peter Stevenson,Dani Johnson/The Washington Post)

Beyond his personal side, Trump hopes the convention projects an image of toughness and resolve to a nation on edge from a harrowing few months that have included terrorist attacks on the homeland and abroad, as well as the gunning down of five police officers in Dallas.

Several scheduled speakers could help reinforce Trump’s claim to be the law-and-order candidate. Among them are former New York mayor Rudolph W. Giuliani, two women state attorneys general and Milwaukee County Sheriff David Clarke, an African American Democrat who is an outspoken critic of the Black Lives Matter movement.

There also will be plenty of Clinton bashing. One evening will be dedicated in part to replaying the former secretary of state’s handling of the 2012 attacks on a U.S. diplomatic outpost in Benghazi, Libya. Two survivors, Mark Geist and John Tiegen, will speak.

“We’re going to continue to pound away and make sure people know what kind of a dishonest, untrustworthy person she is,” Priebus said. “I think Hillary’s on sort of this cruise-control of unlikability.”

The Clinton message machine is not going to cede the stage entirely, however. Her campaign plans to punctuate the networks’ convention coverage with a heavy rotation of anti-Trump ads in battleground states. They amount to a highlight reel of just about every bad moment Trump has had during his year-long campaign. In addition, a phalanx of Clinton aides and surrogates will be in Cleveland offering real-time responses to the pro-Trump programming.

The lineup of Republican speakers is eclectic for a political convention and is intended to root Trump’s candidacy in a culture beyond the political establishment. They include Eileen Collins, the first woman to command a space shuttle mission; Antonio Sabato Jr., a former Calvin Klein underwear model and soap-opera actor; pro golfer Natalie Gulbis; and Dana White, president of the Ultimate Fighting Championship.

One of the biggest stars was to have been Tim Tebow, the deeply religious, Heisman Trophy-winning football quarterback. But anticipation turned into awkwardness. After Republican officials said Tebow would speak at the convention, he put out a video on Facebook saying that those were just “rumors” and that he would not be taking the stage.

In addition, Haskel Lookstein, a prominent New York rabbi who converted Ivanka Trump to Judaism, faced political backlash within his congregation once it was announced he would be speaking. He too decided to back out.

Reaching beyond the usual roster of speakers is partly a necessity, given how many party elders and rising stars declared themselves no-shows in Cleveland — including the GOP’s past two nominees, Mitt Romney and John McCain; its only two living former presidents, George W. Bush and George H.W. Bush; and a number of Republican senators whose reelection prospects have been endangered by the prospect of such a divisive figure at the top of the ticket. Ohio Gov. John Kasich will be in town but provocatively has indicated he would not step foot in Trump’s convention hall.

One eminence who will be here is former Senate leader Robert J. Dole (Kan.), a World War II hero and the party’s 1996 presidential nominee, who will be honored on the convention’s opening night in a veterans’ tribute.

In an interview, Dole, 92, admonished fellow Republicans who are sitting out the convention. “They’re not going to come to Cleveland and speak for Trump,” he said. “I think that’s unfortunate.”

Dole singled out former Florida governor Jeb Bush, whom he supported in the primaries, for continuing to criticize Trump. In an op-ed in The Washington Post on Saturday, Bush wrote: “I do not believe Donald Trump reflects the principles or inclusive legacy of the Republican Party. And I sincerely hope he doesn’t represent its future.”

Dole noted that he himself had attended the 1988 convention after having been beaten in the primaries by Bush’s father, who went on to win the presidency. “I have great respect for the Bush family, particularly Bush 41,” he said.

While Dole thought Jeb Bush was the most qualified candidate this year, “he never caught fire. I’m really disappointed that he’s now — I watched him on TV going after Trump. I mean, Trump was on the stage with him and Trump said some things that I know upset Jeb, but they did sign the pledge. I’m sorry I’m not going to see him in Cleveland.”

Priebus acknowledged that the party still has a lot of work to do to regroup and unify around its nominee.

“There are more bruises than we usually are accustomed to, and the more bruises that you have the longer it takes to heal,” he said. “We’re in the middle of that right now.”

Unity is crucial, both for building a grass-roots organization that can go toe-to-toe with Clinton’s and raising the hundreds of millions of dollars required to wage a credible fall campaign, an area in which Trump has lagged significantly.

“This convention is going to be a unifying convention,” Trump’s campaign chairman, Paul Manafort, vowed in an interview. “We’re going to come out of Cleveland unified with a good field operation, with all the technical requirements we’re going to need and with a candidate that is the epitome of change in a year of change.”

Toward that end, some Republicans warn that substance should not get lost amid the made-for-television spectacle in the downtown Quicken Loans Arena.

“A lot of Republicans who have concerns or questions or doubts about Trump need to hear more from him and his team about policy,” said former Mississippi governor Haley Barbour, who also was once a Republican National Committee chairman.

Barbour said Trump’s team needs to take full advantage of the huge audience to press the case that eight years under a Democratic president have yielded “a record of bad policies that have produced bad results, that Hillary would be more of the same, and here’s what a Trump administration would be like, with some depth. People are really going to be paying attention.”

Ed O’Keefe contributed to this report.