Listen to an excerpt of Michelle Obama's speech for tonight

Just hours before the Democratic National Convention is set to kick off, organizers published an excerpt on YouTube of former first lady Michelle Obama's speech tonight where she praises presumptive Democratic presidential nominee Joe Biden.

The first night of the convention begins tonight at 9 p.m. ET.

Watch the full excerpt here:

Democratic presidential candidate former Vice President Joe Biden and Sen. Kamala Harris participate in a virtual grassroots fundraiser at the Hotel DuPont in Wilmington, Delaware. Carolyn Kaster/AP

The quadrennial national US political conventions are scheduled, even in this time of Covid, to formally nominate each party's presidential candidate and settle on official party platforms for the general election.

Democrats will meet, mostly virtually, August 17-20 to nominate former Vice President Joe Biden. Republicans will meet August 24-27 in Charlotte, North Carolina, to nominate President Trump for a second term — a nomination he's said he'll accept somewhere else, possibly at the White House.

CNN's Zachary B. Wolf talked to Adam Levy, who oversees CNN's political research team, about what's different this year — how things might play out, and whether these things are still important.

Part of their email conversation is below:

Read more here.

A general view of the Wisconsin Center ahead of the Democratic National Convention on August 5 in Milwaukee, Wisconsin. Former Vice President Joe Biden has cancelled plans to travel to Milwaukee for the Democratic National Convention due to health and safety concerns over the coronavirus pandemic. Stacy Revere/Getty Images

The Democratic National Convention is this week, and it won't look like any other in history. Democrats have moved their convention online because of health concerns due to the coronavirus pandemic, and Joe Biden will accept the Democratic nomination for president in a virtual address.

The four nights of programming will feature speeches from politicians, music performances from stars, and will allow Democrats to make their pitch to the American people before ballots are cast this fall.

Here's everything you need to know about how to watch this year's Democratic convention:

When is the convention? The convention is scheduled to take place Monday through Thursday this week, and each night of programming will air from 9 p.m. to 11 p.m. ET.

There will be big speakers:

These musical acts are performing: Leon Bridges, The Chicks, Common, Billie Eilish, Jennifer Hudson, John Legend, Billy Porter, Maggie Rogers, Prince Royce, Stephen Stills and others will be performing throughout the four nights, according to the Democratic National Convention Committee. Youth choir members representing each of the 57 states and territories will also perform the National Anthem Monday night, according to the DNCC.

Where Joe Biden will accept the nomination: Biden will not accept the Democratic presidential nomination in Milwaukee, the original site of the convention, because of concerns caused by the coronavirus pandemic. Instead, Biden and Harris will deliver their convention speeches from the Chase Center in Biden's hometown of Wilmington, Delaware, spokesperson Michael Gwin confirmed to CNN.

Where the rest of the convention will take place: The Democratic gathering will be far different than any in American history, with organizers calling it a "Convention Across America," with speeches and music and other appearances from locations and major landmarks across the country.

Will convention delegates be in Milwaukee? No, the DNCC advised state delegations, including members of Congress, not to travel to Milwaukee because of the ongoing coronavirus pandemic. Jason Rae, the secretary of the Democratic National Committee, informed all certified delegates that virtual voting on convention business would take place from August 3-15.