Fuck around things you don't understand, find out. Why even go near the source control area and start clicking stuff if you don't know jack shit about it.
It seems like he was trying to learn though? He clicked it, like "hell yes I want source control, let's figure this out"
"It says all my files are changed? Oh shit why did it change my files? Shit fuck, undo, how do I undo...Do I want to discard the changes? I don't even know what it changed. Yes please undo whatever changes you did to my files"