Few people are as preoccupied with ratings and audience numbers as President Trump. But when the White House hosts a slate of Ultimate Fighting Championship bouts on the South Lawn on Sunday night, viewers won’t be able to simply flick on their television screens to watch.

The first-ever professional sports event at the White House coincides with Mr. Trump’s 80th birthday, and is billed as U.F.C. Freedom 250. It won’t, however, be carried by broadcast networks or cable stations.

Where can viewers find the fights?

All seven bouts will be streamed only on Paramount+, with the main card beginning at 8 p.m. Eastern time. The paid service, which has around 79 million subscribers, starts at $8.99 a month.

Dana White, the chief executive of U.F.C. and a staunch political ally of Mr. Trump’s, ruled out showing some of the fights on CBS, a Paramount Skydance platform that has a considerably broader reach.

The Trump administration has cleared the way for Paramount Skydance’s planned acquisition of Warner Bros. Discovery, including CNN, after allowing the Skydance takeover of Paramount. The company’s moves have brought accusations of Trump-friendly changes at CBS.

Who is fighting?

The lightweight title bout will pit Ilia Topuria of Georgia against Justin Gaethje of the United States.

In the heavyweight interim title bout, Alex Pereira of Brazil will fight Ciryl Gane of France. Another heavyweight fight will feature two Americans, Josh Hokit and Derrick Lewis.

In the bantamweight category, Sean O’Malley of the United States will take on Aiemann Zahabi of Canada.

The main card also includes a lightweight bout between Mauricio Ruffy of Brazil and Michael Chandler of the United States, a middleweight bout between Bo Nickal and Kyle Daukaus, both American, and a featherweight bout between Diego Lopes of Brazil and Steve Garcia of the United States.

What’s the setup for the fights?

A cage-like ring known as the Octagon will be the focal point on the South Lawn, where a 600-ton steel arch was put up for the event. A temporary arena at the White House will hold more than 4,000 people, according to Mr. Trump. That space will include holders of premium tickets sold by the U.F.C.

A watch party is also being organized on the White House Ellipse grounds, where Mr. Trump has said another 75,000 to 100,000 people could watch the fights for free.