It's a 8v1 survival game, with a roster of characters (and killers) with different skills, abilities, roles, pros, and cons. Survivors can fit into 3 roles: sentinel, support, and survivalist.
f you want to find a survivor that fits your playstyle, you can look at their descriptions! It explains each of their active and passive abilities.
This applies to killers as well. I personally don't enjoy playing as a killer, so I always go to settings and disable the option to be a killer.
You can always search up gameplay, videos, and guides if you don't feel ready. I just jumped straight in and tried out a few characters, until I settled on my main! I main 007n7 :3 He's more known to be a survivalist AKA his kit mainly serves himself and is very good in a Last Man Standing