Win 4 2025 setup

Hello everyone, I am getting my new win 4 delivered tomorrow and was looking for advice for setting it up. I am nowhere near an expert but I did want a quality handheld pc and i was going to try and do it myself but I don’t want to mess up I just want to learn the best way of playing my games, which I plan on playing some like doom or days gone which I already own on steam. Any advice helps, Thank you.