There's AppleTV, AppleTV+, and Apple's TV app
AppleTV is the box
AppleTV+ is their streaming service, similar to Netflix or amazon prime. It's a paid subscription, but you may receive a free trial when you buy the box. There are quite a few really good shows... For all Mankind, reverence, morning show, silo, ted lasso.
the TV app, is one of the nice features of the appleTV box. It can consolidate most of the other streaming apps (Netflix being a major exception). You can search in the TV app, and it will tell you where you can watch and how much it will cost, so maybe rent from apple for $5, buy from apple or amazon for $19, or included with a peacock subscription. It also has an "up next" section that helps you keep track of shows, anything you watch on any of the supported services is automatically added to the up next section. When you finish an episode, it will put the next one there for you. Or if you're caught up, when the next episode drops, it shows up there. It's really convenient if you have a lot of services, since you only have to check one place to see what's new. When you select the show, it will launch the app for the service to actually watch the show
The TV app is also used to watch the shows from appleTV+, their shows will appear just like the ones on the other services, but it will play in the TV app instead of launching a new app.
The Siri Remote that comes with the appleTV box is also fairly nice, If your TV (and sound equipment if you have it) support HDMI-CEC, then you just need the siri remote, When you hit the power button on the remote, it will all turn on and the TV and audio gear will go to the correct channel. and you're able to control volume with the same remote. If you don't have HDMI-CEC it will still work using IR, but it's sometimes a little picky. It also has siri built into the remote, so just hit the button and say "Launch Netflix", "search YouTube for cat videos" or just "game of thrones"
list of siri commands from apple -
https://support.apple.com/en-us/105019