I downloaded the trial, and I have to agree the instructions are mostly written as if the reader already knew the answer. I'm still not sure what it is supposed to do and I am totally at sea on what gestures to program much less how.

Never the less, I have not encountered any unexpected shutdowns with BTT. As an aside I was having unexpected shutdown issues with a couple of apps, one of them an app that is internal to MacOS but the MacOS 10.15.4 beta cured the problem with both apps. 10.15.4 should be in general release soon and may solve your problem.

THANKS While looking for Better Touch Tool I encountered Better Snap Tool which is turning out to be helpful in managing windows between my two monitors. It really doesn't do anything that could not be done manually, but it is a lot quicker and reasonably intuitive to use in tiling and arranging multiple active windows.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein