On Sunday afternoon, the National Baseball Hall of Fame will induct its new class. There will be six former players enshrined in Cooperstown, including Mariano Rivera, the late Roy Halladay, Mike Mussina, Edgar Martinez, Harold Baines and Lee Smith. Here's a primer on Sunday's events, including how you can watch the ceremony.

2019 Baseball Hall of Fame induction ceremony

Time: 1:30 p.m. ET
Date: Sunday, July 21
TV channel: MLB Network
Live stream: MLB.com

Here, then, are five things you need to know about the Hall of Fame class of 2019.

1. Unanimous Rivera headlines the class

If you haven't heard by now, longtime New York Yankees closer Mariano Rivera became the first player to ever receive a vote on 100 percent of the ballots. Previously, Ken Griffey Jr. held the distinction of appearing on the highest percentage of ballots, with 99.3 percent in 2016.

Rivera reflected on the honor during his pre-induction media availability, saying, "That's special to me, and I carry [it] with dignity and humbleness that I don't deserve it.

"I don't consider myself better than anybody else -- I don't assume that I was better than anybody -- but one thing I did, I did my best. I did my best for the game of baseball, to respect the game of baseball, and to respect the other teams and [my] peers."

Rivera finished his 19-year career with a record 652 saves and a 205 ERA+.

2. Martinez owned Rivera

For as great as Rivera was, fellow Hall of Famer and former Seattle Mariners DH Edgar Martinez had his number. For his career, Martinez went 11 for 19 with two homers, six runs batted in, and a .579/.652/1.053 slash line. You read that right -- a 1.705 OPS versus the greatest reliever of all-time. Wild, huh?

Both Martinez and Rivera talked about their head-to-head battles. Martinez credited his success to his approach, noting that he would tell himself, "OK, just look middle-away and try not to do too much. Just try to make solid contact." He added: "Every time I tried to swing hard against Mariano, I was late or I missed." 

Rivera, for his part, infused some humor into the narrative, joking that Martinez was only in the Hall of Fame because of him -- and that Martinez owed him dinner as a result.

3. Halladay becomes sixth posthumous inductee

Unfortunately, part the ceremony will have a somber tone. Roy Halladay died in a plane crash in 2017, but during his career he served as an ace for both the Toronto Blue Jays and Philadelphia Phillies. The right-hander amassed eight seasons of 200-plus innings and won two Cy Young Awards.

Halladay became the sixth player to be voted in by the BBWAA after his death, joining Christy Mathewson, Willie Keeler, Herb Pennock, Harry Heilman and Rabbit Maranville.

4. Mussina's cap won't have a logo

One of the big questions after Mike Mussina was elected to the Hall was whether his plaque would include a Yankees cap or a Baltimore Orioles hat. The answer? Neither. Instead Mussina's plaque won't include any logo on his hat, as he felt both organizations were "instrumental" in his reaching Cooperstown in the first place.

Halladay's plaque will also not feature a logo. Baines (White Sox), Martinez (Mariners), Rivera (Yankees), and Smith's (Cubs) will, however.

5. Smith and Baines make cut

Lee Smith and Harold Baines don't get talked about as much as the rest of the class. Both will receive some shine, though, thanks to the Today's Game Committee. Twelve votes were needed from the committee's 16-person panel in order to earn enshrinement. Smith received 16; Baines 12; and Lou Piniella came up just one short. 

During their time on the ballot, Smith never received more than 50.6 percent of the vote. Baines, meanwhile, topped out at 6.1 percent. You can argue about whether they deserve inclusion, but clearly they're in and that's not going to change.

Smith, for his part, seems humbled by his inclusion, noting that just over 200 individuals -- from the countless players over the course of baseball history -- are in the Hall. "I'm like, man, I came from a town that didn't have a red light. You just think about things like that."