Not sure what your experience is in debating, but Trump lost all three massively because he failed to construct an argument at any point.
Hint: These aren't debates in the usual sense of the word. These are Reality TV infomercials for the D & R candidates. A real debate would ask both candidates what they believe on question 1. Candidate A would give their answer, and Candidate B would give their answer. If they disagreed, Candidate A would get a response, followed by Candidate B. Next question would start with question 2 starting with Candidate B, and so on. You'd have questions about policy issues, not "Have you stopped beating your wife?" gotchas. Instead what we get are pissing wars where everyone gets wet. I think Trump is a doofus, that doesn't mean that he didn't perform better in these Reality TV episodes.