I'm really not sure how to go about this
I also have no idea what a good roll would be for maximizing attribute points. What would be a good roll?
I don't save a character unless their total attributes have a sum of 92 or better. My best ever roll is 97, which is an average of 16 in each stat, which honestly is pretty absurd.
You'll want STR 18/something, DEX 17+, CON 16-17, INT 18. WIS and CHA can be dump stats, since you'll get potions and items that can increase these. Non-fighter-type classes don't get any bonus for CON past 16, so there's little reason to go over that. Higher STR/extra numbers are better, but don't stress about these too much. As long as it's at least 18/01 you're doing well. Note that only fighter-type classes get the extra number. Your DEX should be as high as possible regardless of class. Also note that for most stats, you don't get ANY bonuses if the stat is lower than 15. This is one of the weirdest quirks about the 2nd edition AD&D system that BG uses. A character with 14s in each stat is functionally equivalent to a character with 9s in each stat.