My way is to rewrite out my notes from my book (if their good). If their not good I would use a website called ‘PhysicsandMathstutor’.Then find another source of notes such as a revision guide and read them alongside each other to make sure you have everything.Then test yourself on things like equations or simple facts.Once you feel you know most of the content do exam questions (also from PhysicsandMathstutor).If u don’t understand a certain part then watch a video on it.