This is more of a blanket question than specific, but in my case I have a program I was given, but unfortunately it's broken. (It worked before, which was a while ago)
The program is a C# WPF .exe, but I'm just learning programming and I have no clue how to fix it. I can view the code behind it, I think, when I decompile it (dotPeek, but it seems to be read only), but I've no clue how to edit and recompile the program to work just like previously. I tried googling but I wasn't sure what terms would answer this question and the ones I've used proved fruitless.
Tl;dr - how to modify programs (especially C# WPF .exe)