How to play backwards compatible PlayStation 4 games
The PS5 will be able to play nearly every PS4 game that’s available through backwards compatibility. Sony also promises that some games will actually be able to take advantage of the extra power on the new console to provide a “Game Boost” for faster or smoother frame rates. That said, Sony also warns that some functionality from PS4 titles may not be available, and there may be “errors or unexpected behavior” when playing backwards compatible titles on the PS5.
Playing PlayStation 4 games off a disc (PlayStation 5 only)
The simplest way to play backwards compatible games (assuming you have a PS5 with a disc drive and a hard copy of the game) is to simply put the disc into your PS5. Some games will require an update to be installed, but beyond that, it’s just plug and play.