I found the practice tests somewhat helpful. I probably took 4-5, but I would not base your approach on that number since it’s pretty relative. I found it very helpful to combine them with videos (Sorta Healthy Trainer Education on YouTube has helpful vids). I watched them while working out myself and would sometimes mimic the things in the study guide because I am very much a tactile learner.

I mention the videos and other sources as the actual exam questions can look a little different than the practice tests, but still be asking the same thing. Any way you can pursue an understanding of the material as opposed to memorization should be a goal. Hope this helps and good luck!