There’s a separate tab for Apple TV+ content. You can also use the channels section or find the tab in the search area.My free trial would have expired on Oct 2 but I've decided to cancel two months early because there is literally nothing on there that I would like or enjoy watching. The only reason why I subscribed to the free trial to begin with was Ewan McGregor's and Charley Boorman's Long Way Up, which ended up being somewhat disappointing (not Apple's fault obviously). I tried to browse the AppleTV+ catalog afterwards to find other stuff worth watching but it was too confusing as there was no clear distinction between a show or movie that is included in AppleTV+ and one that I have to purchase and pay for separately.
Not sure if that changed since as I gave up two weeks into my trial and almost exactly 30 minutes after I finished watching Long Way Up and never turned back. Not worth my time and money.