Tutorials - Kieranator/BadArma GitHub Wiki
Editing Arma isn't that difficult, but it has a steep learning curve. SQF syntax is ugly, and the mission editor is not intuitively designed. These tutorials will help you get over that initial hurdle so you can build virtual murder fast.
#Video Tutorials
There are a lot of good video tutorials for the Arma 3 editor and scripting. Most of them start out very simplistic and ramp up in complexity to show off different features of the editor. If you're looking for something specific, they probably have a video showcasing it.
Jester814 has a collection of video tutorials that are really useful to beginners. If you start from the beginning of the playlist at the bottom, his videos will cover just about all you need to know for the simple point-and-click editing as well as a decent amount of SQF scripting.
Killzone Kid has a whole range of tutorials on sqf scripting and GUI work. Very interesting.
#Text Tutorials
These exist, somewhere.
WIP