You have a poor foundation. First of all, I suggest you do the classic examples and after-school exercises in the textbook several times, and then do other topics. At first, you may not be able to do it right at once, but you will have ideas in your mind, and you will naturally learn math well by doing more exercises slowly. In fact, the Century Gold List and the middle school teaching materials you mentioned have their own characteristics. Compared with your situation, I feel that the middle school teaching material study handout is more suitable, because it explains in detail, better grasps the teaching material and the examination direction, and there are also exercises with appropriate difficulty behind it.