[1] Right click the download button and select the 'Save link as...' option.

[2] Save the file into the following directory, or save it anywhere and then move it here:
C:\Users\Your Name\Documents\Superfighters Deluxe\Scripts

[3] Rename the file; this step is important as you'll be required to write the file name along with the command to activate it any time you want to use it.

[4] Make any desired changes to the script or its settings.

[5] Save the changes, then go in-game.

[6] When in-game, write the following command into the chat:
/startscript filename
Instead of "filename", write the name of the file you chose in step [3].
Be sure to write it correctly otherwise you won't be able to activate it (for example, if I name the file
mod.txt I will write /startscript mod in-game).