Long-Term Test Prep Plan

I’m an incoming freshman, so I know it’s a little too early to start thinking about this, but how should I formulate my long term test prep plan? What I mean by that is how should I plan everything out so that I would be finished taking the SAT 1 towards the end of my sophomore year? (which is also when I am required to take the PSAT)
I know most people take the SAT their junior year but I want to get the SAT 1 out of the way so that I can focus on SAT subject test (US History, Math 2, Chem, Bio, Physics, ect)
I have Kaplan’s New PSAT Test Prep book and three weeks of summer left, so if anyone can give me some advice on how to plan accordingly for the short time frame I have for the SAT that would be great. Should I use the one practice test in the book before or after using the book?
Also please recommend other study material/ workbooks I should use for the PSAT and the SAT 1 and things you regretted while prepping for the SAT (or lack of). Thanks!