Hello FXtalant,
the good thing with the courses is that they are independent. Each course provides different system, strategy, Expert Advisors and at the same time you do not need any of the courses in order to take certain course. Which means that which ever course you select as a first will be useful.
I would suggest you take the Basic Algorithmic trading as a first first course if you do not have any experience in alto trading. I did it first and after that all the other were fluent to me. At the same time you get 3 experts there that Petko updates all the time.