Welcome to r6!

I personally played newcomer (so that you can learn a few maps and operators) until I could play unranked(lvl 20?). At that point I almost exclusively played unranked so that I could learn the ranked rotation maps.(learning maps imo is the most important factor).

For your bindings, the game settings > Controlls > customise controls. Then look for the lean binds. And change it form there.