Yep, so basically, you just create a shortcut to the program.
Right-click it, select properties. And assign the shortcut keys you want.
But, if it's in a program, like CTRL+S to save, it depends on the program for ways to set shortcut keys.
Like, in a lot of them, you go to Tools>Options and you can change shortcut keys there, but that only works for some programs.
Go read a different signature.