@claudee first listen from someone or read the main keys of the topic , note the formulas as well and jump to the questions try them yourself first , if you can't solve , look for the answer and detect the reason why you can't solve , try the same type questions again until you solve it , the topics are connected so eventually it will be easy for you , a lot of formulas can dedicated by another formulas as well , main key is understanding at the end of the day or you will just pass the test and forgot everything by tomorrow.