TFT Logic? HELP PLEASE! Anyone?

So i understand the basics of TFT set 2 but i don't know what im doing when it comes to what comps counter each other, what comps are best on each element board, what items are best on each champ, or where to place them to gain maximum potentials of winning. Where do i go to learn all this bc i have looked at countless YouTube videos and haven't learned anything useful. Or does anyone have some info i could use to improve?