President Trump speaks to reporters as he departs for travel to Utah from the White House in Washington, U.S. December 4, 2017. (REUTERS/Jonathan Ernst)

Since news broke that former national security adviser Michael Flynn was pleading guilty to lying to the FBI on Friday, there have been a slew of new revelations related to the government’s investigation into Russian meddling — so many that those not actively paying attention over the weekend may need to be brought up to speed.

When we say “the Russia investigation,” we are admittedly using a broad descriptor for a range of possible improprieties. The densely packed tree rooted in how Russia apparently tried to interfere in the results of the 2016 election has, for example, a leaf labeled “Paul Manafort” that sits at the end of a thick branch titled “Donald Trump campaign.” Another branch labeled “Trump’s response” has a smaller offshoot called “Firing of James Comey.” Or perhaps, given the weekend, a better metaphor is a hydra, with Trump’s battles against it often leading to new problems for him to fight.

Regardless. Here’s what we know now that we didn’t know on Friday morning.

Two senior transition officials guided Flynn as he reached out to the Russian ambassador. The charge that Flynn lied to the FBI stems from his answers to questions earlier this year about a series of conversations he had with Russian ambassador Sergey Kislyak last December, after Trump won the election. (Here’s a full timeline of what happened.)

One set of conversations shortly before Christmas involved a United Nations vote on a resolution condemning settlements in Israel. Flynn was reportedly asked by President Trump’s son-in-law Jared Kushner to contact various foreign actors to encourage a “no” vote on the resolution. As The Post reported shortly before those calls were made, his family’s foundation had made a series of donations to support the settlements, which the U.S. government has long considered illegitimate.

The more significant conversations involved calls between Flynn and Kislyak shortly before the new year, when the administration of Barack Obama, responding to Russian meddling in the election, announced sweeping new sanctions against the Russian government. Kislyak reached out to Flynn about the sanctions, who then discussed the Trump transition’s response with his eventual deputy at the White House, K.T. McFarland. (She was eventually tapped to serve as ambassador to Singapore.)

McFarland emailed transition team members with questionable comments about Russia’s activity. At some point on Dec. 29, 2016, the day that Flynn and Kislyak spoke multiple times about the sanctions against Russia, McFarland emailed Tom Bossert, then another transition official and now Trump’s homeland security adviser. The New York Times obtained copies of the emails, which Bossert forwarded on to others on Trump’s team.

McFarland viewed the Obama team’s actions as being at least in part politically motivated: discrediting Trump’s victory, setting a trap in which Trump denied Russian interference and to try to box him in.

Her statement that Obama sought to make it difficult for Trump to improve relationships with Russia “which has just thrown USA election to him” and that Russia might have been caught “red handed” in meddling raised eyebrows when reported, but the context suggests that this may have been her interpretation of the view of Obama’s team. The flatness of the statements, though, prompted a number of questions.

Flynn ultimately asked Kislyak to have the Russians not escalate a response, which they didn’t, earning Trump’s praise. In a call on Dec. 31, Kislyak credited Flynn with their not doing so.

Trump’s lawyer claims that the president believed that Flynn had lied to the FBI when he fired Comey. On Jan. 20, 2017, Trump was inaugurated and two days later Flynn was sworn in as national security adviser. Two days after that, Flynn was questioned by the FBI and denied having spoken to Kislyak about sanctions. That’s the assertion that led to Flynn’s charges last week.

On Saturday, though, a tweet from Trump added a new layer of questions to the timeline.

Trump’s statement that he “had to fire General Flynn” because he had lied to the vice president “and the FBI” was not something that had been said before.

In the eyes of outside legal observers, this is problematic because it implied that Trump knew that Flynn had lied to the FBI when he reportedly suggested to then-FBI director James Comey that he should stop pursuing charges against Flynn. (Under oath, Comey testified last June that Trump said “I hope you can see your way clear to letting this go, to letting Flynn go. He is a good guy. I hope you can let this go.” He claims to have contemporaneous notes from the meeting that outline the same comments.) If Trump knew that Flynn had committed a federal crime, asking Comey to not charge Flynn might bolster a case for obstruction of justice against the president.

At first, the White House claimed that the tweet was a poorly worded statement that had been crafted by Trump’s attorney John Dowd. In a statement to The Post on Sunday night, though, Dowd stated that the crux of the claim was true: That Trump had, in late January, known that the lie Flynn had allegedly told Pence — that he hadn’t discussed sanctions with Russia — was the same claim that he’d made to the FBI. Flynn was fired on Feb. 9 for lying to Pence; according to Comey, Trump suggested to Comey on Feb. 14 that he not push forward on his investigation.

To Axios’ Mike Allen, Dowd made another claim: While the tweet didn’t prove obstruction, it doesn’t matter, since “the president cannot obstruct justice” in a legal sense. This is not a universally agreed-upon legal opinion.

Another Trump adviser tried to establish a connection with Russia. In May 2016, a Trump campaign aide named Rick Dearborn — now a deputy chief of staff in the White House — received an email from conservative activist named Paul Erickson with the subject line, “Kremlin Connection,” according to the New York Times.

That email appears to have been one of several attempts to connect the Trump campaign to a man named Alexander Torshin, who had also asked another ally to contact the campaign on his behalf. That email was titled “Russian backdoor overture and dinner invite” and was sent from Dearborn to Kushner, who rejected the outreach.

Despite that, Torshin ended up seated next to Donald Trump Jr. at a dinner at the NRA’s annual convention in Louisville at the end of that month.

An FBI agent on Mueller’s team was removed for anti-Trump text messages. A month or two into special counsel Robert S. Mueller III III’s investigation into the Russian meddling effort, an FBI agent assigned to his team was reassigned within the agency after text messages disparaging Trump were discovered.

The agent, Peter Strzok, was an integral part of the investigation into Hillary Clinton’s email server. The messages between him and an FBI attorney named Lisa Page were not described in detail, but apparently were reactions to campaign news during 2016. He was reassigned in July; Page, who’d been on Mueller’s team as well, left prior to that.

Trump, as might be expected, tweeted about this, too.

In all fairness, we’re still some ways from having it all make sense.