1. Buy and install OTXO (if you haven’t already)
2. Go to the installation folder and open script_english.ini
(If you don't know how to find it, right click OTXO on your Steam Library -> Properties - > Installed Files -> Browse!)

You can use any word processing software to edit the text in the file, you should be seeing something like this:
3. Edit anything here to your liking!
(This one is mine for reference)