STEP ONE:
open the game (if you don't know how to, I'm sure there's a lot of tutorials)
STEP TWO:
select create a new game, skip the Makoto's yapping about the school and wait until the introductions moment
STEP THREE:
fall in love

You still want more than just seeing your character? I HAVE A SOLUTION: GET THEIR UNDERWEAR!!!!!!!!
--> complete all the chapters
--> open school mode
--> use a trip ticket while hanging out with your desired character(s). You can earn up to one heart (depending on your answer choice) per one trip, and you need to get 10 hearts (you can check them by interacting with monokuma during free time, this wont make you lose anything) and you need to get warlockuma to trigger the ending after 50 days pass, giving you the underwear of your waifu/husbandu (whatever you call that)
Also, to get trip tickets you need to do monokuma's tasks - the first one that you have to do gives you 5 if I'm correct - i only did another one besides that and it granted me another 8 tickets, enough to trigger the ending.

*Getting underwears is needed to get the achievement where you need to get every present*
HOPE I HELPED YALL AND PLEASE DON'T GET TOO OBSESSED WITH THEM (or do, I don't care) (as)