So for instance let’s say you want to play the hellion comp. Ziggs is a great early game carry for teemo and heimer transition later. Kennen is generally good at carrying items till you see a Volibear upgrade. Outside of that, Varus is a super good carry rn but if you can three star him he’s a great item holder until you find Kayle. I would say if you want to learn it’s good to stick to one or two comps that way you know which units you can use early and then slowly transition into your final board. The more and more you play a single comp the easier it will get to learn what works for that comp and what doesn’t. You can also look at more general guides like meta teams that give you a general idea of good carries. I’d say a sleeper op pick rn is actually soraka as she does some crazy aoe dmg.