Hello there! 

Greetings! 

Maths is all about understanding concepts and then applying them. So first of all you need to understand formulas and their application;  for that you need to first go through all the solved examples , it will help you to understand, the approach for solving questions and then go for solving excercise questions. If you are from cbse board, then first complete ncert , ncert is the key to score good marks in board exam.

Thankyou