The quote you gave assumes you have a basic understanding of the command line.
Edited for being wrong.Anyway, let's break down the quote you were having trouble with:
QUOTE
Do you know the full path to your file? If you don't feel like typing in the entire path, then simply navigate to the folder. If you have the ability to open a command prompt by right clicking on a folder, that's even easier.
What this means is you're supposed to use the command line to navigate to where the file you want to modify is. You can either do this by "typing in the entire path," for example,
CODE
CD "%UserProfile%\Desktop\ModifyPE"
or by "navigat[ing] to the folder" using multiple CD commands:
CODE
CD "%UserProfile%"
CD Desktop
CD ModifyPE
"If you have the ability to open a command prompt by right clicking on a folder, that's even easier." This is referring to a tweak that adds the ability to right-click on a folder in Windows Explorer and open a command line directly to this folder. It is the same thing as typing either of the above commands.
Lastly, the actual command and modifying the file. Make sure ModifyPE.exe is in the same folder as the file you want to modify, then type
CODE
ModifyPE.exe <filename> -c
where <filename> is the name and extension of the file you want to modify, which will usually be a dll (but doesn't have to be). You should see "No Error occurred, have a nice day" in the command line. If you get an error, please post it here and someone can give you more specific help.