Solving problems does take time, but it is usually time well-spent. You can learn a fair amount by watching the author develop the material, and by filling in details in the text. But, you learn far more by doing as many exercises as you can. Exercises develop technique, knowledge of and facility with the theorems and definitions, and give you the opportunity to solidify the material in your mind. You really don't get these benefits any other way. As former American Secretary of State Colin Powell said: "There are no secrets to success. It is the result of preparation, hard work, and learning from failure." So, get working on those exercises. Do as many as you can, and ask for help on the rest.
P.S. My remarks are predicated on the assumption you really want to learn this material. If you want only to be acquainted with it, you can get by with a lesser investment of time, but you still will need to do a fair number of problems (perhaps half of them, or, maybe fewer).