The crew gets ready for a vice presidential debate at Longwood University in Farmville, Va., on Oct. 3, 2016. (Chip Somodevilla/Getty Images)

The first official Democratic presidential primary debate is a big deal for the 20 candidates who qualified to be on the debate stage.

“You get one chance to make a good first impression,” said Democratic strategist Mary Ann Walsh.

Here’s how to watch the debate, from how to watch to what to watch.

When is the Democratic debate?

Date: June 26 and June 27

Time: 9 p.m. to 11 p.m. Eastern time

Where: The debates will be held in Miami, but you were probably asking where on the TV you can watch it. The answer: NBC, MSNBC and Telemundo.

Why are there two nights? Because so many candidates qualified for the debate thresholds, the Democratic National Committee split them up between two nights, with 10 candidates on each stage. Most candidates are randomly selected for each stage, but the DNC spread out the top-polling candidates between the two stages.

Who’s on which stage?

On Friday, NBC announced the lineup.

June 26 debate

Castro

de Blasio

Delaney

Booker

Gabbard

Inslee

Klobuchar

O’Rourke

Warren

Ryan

June 27 debate

Bennet

Biden

Buttigieg

Gillibrand

Harris

Hickenlooper

Sanders

Swalwell

Williamson

Yang

Did not qualify for the first debate

Bullock

Moulton

Messam

Source: NBC News

SHELLY TAN/THE WASHINGTON POST

June 26 debate

de Blasio

Delaney

Gabbard

Booker

Castro

Warren

Inslee

Klobuchar

Ryan

O’Rourke

June 27 debate

Bennet

Biden

Buttigieg

Gillibrand

Harris

Sanders

Swalwell

Williamson

Yang

Hickenlooper

Did not qualify for the first debate

Bullock

Messam

Moulton

Source: NBC News

SHELLY TAN/THE WASHINGTON POST

June 26 debate

de Blasio

Delaney

Gabbard

Booker

Castro

Warren

Inslee

Klobuchar

O’Rourke

Ryan

June 27 debate

Gillibrand

Bennet

Biden

Buttigieg

Harris

Hickenlooper

Sanders

Swalwell

Williamson

Yang

Did not qualify for the first debate

Messam

Moulton

Bullock

Source: NBC News

SHELLY TAN/THE WASHINGTON POST

June 26 debate

Booker

Castro

de Blasio

Delaney

Gabbard

Inslee

Klobuchar

O’Rourke

Ryan

Warren

June 27 debate

Bennet

Biden

Buttigieg

Gillibrand

Harris

Hickenlooper

Sanders

Swalwell

Williamson

Yang

Did not qualify for the first debate

Bullock

Messam

Moulton

Source: NBC News

SHELLY TAN/THE WASHINGTON POST

June 26 debate

Warren

Booker

Castro

de Blasio

Delaney

Gabbard

Inslee

Klobuchar

O’Rourke

Ryan

June 27 debate

Harris

Bennet

Biden

Buttigieg

Gillibrand

Swalwell

Williamson

Yang

Hickenlooper

Sanders

Did not qualify for the first debate

Bullock

Messam

Moulton

Source: NBC News

SHELLY TAN/THE WASHINGTON POST

Who are the moderators? “Today” co-anchor Savannah Guthrie, “NBC Nightly News” anchor Lester Holt, “Meet the Press” moderator Chuck Todd, “The Rachel Maddow Show” host Rachel Maddow and “Noticias Telemundo” anchor José Diaz-Balart.

How will the questions be decided? That will be up to NBC. They are soliciting questions from people here.

When are the next debates? July 29 and 30. There will be 12 Democratic primary debates overall, six in 2019.

What to watch for

1. Is anyone going to have a breakout moment? Is one even possible? The debate will be unruly: Twenty candidates and five moderators will be spread over two nights. The current leaders in the polls aren’t even on the same stage. The closest precedent to this is the early 2016 Republican primary debates, in which the top 10 candidates were invited to a main debate and there was an “undercard” debate earlier in the day. There was a lot of back-and-forth, even some shouting. In the end, one person dominated — and that person is now president.

2. Does Joe Biden engage with the other candidates? The former vice president has been running his race as if he’s already the nominee. He’s not schmoozing nearly as much as the other candidates on the campaign trail, which he can afford to do because he’s leading in every major poll. But for at least one night, he’ll be sucked back into the primary for this debate, with a target on his back. Speaking of ...

3. How does everyone else go after Biden? One good way to get yourself heard is to draw a contrast with Biden — maybe even draw blood from him, says Walsh. But so far, most candidates have avoided directly criticizing Biden, and certainly not by name. Does that change in the first debate? “At some point, the debate is going to get much sharper,” said Democratic strategist Jim Manley. Going after the leader in the polls is simply what one has to do to get noticed.

4. How do all the women onstage change the dynamic? This field is one of the most diverse in history. Six of the 20 candidates in the debate will be women, a first for any major party. Do they talk about their gender, even own it, in a way female politicians haven’t in the past? How could their presence trip up any of the men or moderators?

5. How do the most successful candidates contrast themselves with Trump? Who’s most electable against Trump is a thick undercurrent in the Democratic primary. “Electability” is a subjective (and at times, gender-biased) term that voters are wrestling with. To that end, every candidate is going to want voters to imagine they’re debating Trump — not other Democrats — onstage. There’s no consensus on how to successfully do that. Biden is already talking about Trump by name more than most candidates, but does he get in a back-and-forth with Trump, via social media or cable news? Does he respond to Trump calling him “the weakest mentally,” for example? Do the candidates try to focus heavily on policy rather than personality and just ignore Trump? Some candidates are signing onto a pledge not to use stolen information in their campaigns, for example. And how does all of this play into the broader Democratic debate about how antagonistic to be toward Republicans?

6. How many times is “socialist” mentioned? Another defining debate of the Democratic Party is whether it’s moving too far left (by proposing government-run policies like Medicare-for-all), or whether that’s exactly what needs to happen to beat Trump. Jim Kessler, a Democratic strategist with the centrist Third Way think tank, suggested keeping an eye on whether candidates use the term as an epithet or a point of pride.

7. How negative does Bernie Sanders go? A couple of strategists mentioned to me that if any candidate is going to take his or her gloves off, it’s likely to be Sanders. He is not a conciliatory politician by nature. He’s already gone after Biden. But we may see Sanders on the defensive, too. In the 2016 primary, Hillary Clinton largely avoided attacking him. Given he’s second, behind Biden, in many polls, we could witness Sanders on the defensive for the first time.