Here's a trigger tutorial they made for HotS collector edition -->
& cutscene editor tutorial -->
Biggest tutorial for me at least was to just open up blizzards & and other creators maps and look how they do stuff.
Mapster
SC2Mapster has large quantity of helpful tutorials (https://sc2mapster.gamepedia.com/Tutorials) and forum threads, they tend to be harder to find but with some googling and searching you can usually find an answer or make a thread asking for help yourself.
Blizzard
Here's a trigger tutorial they made for HotS collector edition -->
& cutscene editor tutorial -->
Mapster
Youtubers