I'm a 4th year IMG from Colombia, and I want to start my preparation for the Step 1

Hi guys! I’m a 4th year IMG from Colombia, and I want to start my preparation for the Step 1. I have noticed that my basic concepts from year 1 & 2 are extremely weak, and I think I’ll need to take a whole year of dedicated prep.
I have been collecting all sorts of books (First Aid, Pathoma, BRS physio) and videos (Pathoma, Sketchy Micro & Pharm) as well as Anki decks (Zanki).
I’m planning to start by January 2020 and then I’ll get the UWORLD licence and I’m deciding whether a Kaplan on demand course would benefit my preparation.

My biggest concerns are the following:

  1. Am I missing any other source to study from?

  2. How should I build my schedule? I mean, should I start studying certain sources first, and the rest of them (taking in count that I’m planning to do 1 full year, and also that my basic concepts are almost non-existent)

  3. Is Kaplan on demand course worth it? Should I get it from the start?

Thanks in advance and I apologise for such a huge post