Each Expert Advisor, free or very expensive, works according to a well-defined algorithm based on one of the trading methods. This can be trend trading, scalping, pipsing, breakout trading, etc.
Therefore, for a start, you need to decide which approach to trading you like, in which you have more understanding. It is highly desirable that you have some kind of experience in this particular type of trading, it will help you make sure that the Expert Advisor is functional.
