According to my previous experience in studying mathematics and physics (full marks in each subject), my approach is: you should go from books to exercises, from simple to complex, from easy to difficult, from shallow to deep, from slow to fast.

First of all, you should read through the book, understand the knowledge points above, and then do some related questions according to the knowledge points. You should do something simple first and go deeper and deeper. As for the simple to complex, that is, you first do a question that contains a single knowledge point and can summarize the knowledge points, and then slowly change to include multiple knowledge points. As for from slow to fast, it is aimed at the auxiliary exercises in the usual exams to gain time for the exams. At the beginning, don't pay attention to quantity, pay attention to quality first. Even if you do one thing a day, as long as you do it right, you will still get something, but if you do a lot a day, it is all wrong, and it is futile. After ensuring the quality of your questions, speed up slowly.

You are still early, and you are only a freshman. This method should be very applicable. You'd better make a set of wrong questions, classify your own wrong questions, summarize the reasons for the mistakes, and summarize the knowledge points to see if you have mastered them.