Kaplan (Lessons on Demand, Subject Tests, Diagnostics, etc...)

So I took 1 Kaplan Practice Test from Kaplan Book code. And as I was going over the answers I found a link on on my Kaplan Account that gave me access to all of these other resources, videos of online lectures, quizzes, subject tests, 3 additional practice tests, diagnostic exams, natural science test..... I had no idea that I even had this until now.. The book basically only mentioned the free practice tests it came with, where did all of these come from?

Has anyone used these and if so,...

Kaplan (Lessons on Demand, Subject Tests, Diagnostics, etc...)