This is a practice test, so the only preparation I would do is to take a sample test once or twice at the dining room table. You can find them in Kaplan PSAT books at the library, and your school probably has them, too. (My son found an error in his Kaplan SAT prep test last year, so if your son gets an answer wrong, check the explanation which might be different than the answer key. Ugh.)
DS15 did great on the ACT (3 times, no writing) so I was surprised his SAT (through NUMATS) was not nearly as good; in fact, middle of the road. I asked about that here, and the answers were that it's a vey different kind of test from the ACT.
