Lot of stuff here file association needs reconciling
Any plaintext editor (such as Notepad) can be used. Avoid using word processing apps such as WordPad, Word, or LibreOffice, as these would typically add metadata to the text that corrupts the file. Editors such as Notepad++1) can assist with syntax highlighting, auto-completion, formatting, and indentation.
It is highly recommended that you download and install Notepad++ before you open a 4RPL file to ensure that the correct file association is established. If you have already established a file association, see below for instructions on how to change file associations.