first you press the power button, then wait for the console to load (5-10s usually for a Switch), then dismiss the ads asking you to buy or subscribe to something, then navigate to the game you already have inserted into your console, then press play, then confirm you DON'T want the recommended update (which prevents you from playing the game), then accept the update when you realize it stops you from playing the game, then wait for the update to finish (10-30s + a console restart), then accept the System update which didn't even pop up before (another 1-2m + restart), then finally go through the above again, and now.... you're finally at the main menu of the game
sorry i just tried picking up the Switch again today during my sick day and had to wade through all this just to play Metroid Prime (a game that came out a decade ago)