Here's a guide https://www.youtube.com/watch?v=eoxl2fF9H4w

if you don't have the time, I suggest refines especially at early stages of the game. Suggest getting medium instead of basic, since basic is redeemable through ranked battle shop. Charms scale to ur refines+strengthen, so i highly suggest getting that later on. Power>Ninjas. You can get ninjas later on. Gl with getting #1 :D