"learn me"?? How about "educate me".
It's going to be a LOT more than just a simple hex editor. You've going to have to figure out how resources are stored in an .EXE and move things around while maintaining the integrity of the .EXE file. You can't just move data around and expect it to magically work. The .EXE format expects things to be in very specific places as specified in the tables inside the .EXE.
If you're going to move stuff around to make room for your "edited" text, you're going to have to move other things and update the pointers to them. This is FAR from trivial.
You can start by reading the
Microsoft PE and COFF Specification[
^] documentation. Then you can read
this[
^] and figure out how to use and understand the DumpBin tool in the .NET SDK.