Hello,
I am far from being the most experienced in this area so answer here may appear as self-evident but first you may want to see if Scarlet cannot make the .exe modification you want, as it is quite easy to use and has many features.
If the modification you want cannot be done by Scarlet you may be indeed forced to do so with an hex editor, but with the condition of knowing the right adresses and the right bytes to replace in order to have the expected effect.
Maybe you could explain here what exactly you want to do with the .exe, as if someone replies it can be useful for someone else too.
