To clarify (and for anyone else reading) after you have enabled Aric's mod and it is working correctly you would want to insert the code into the game files within the main Strive game folder. Typically when I am writing any code for Strive I edit the game files directly so that I can see code changes immediately upon reloading the game. This of course means that if you go back into the mod options and disable the Aric mod you will lose all of your code changes (which is why I also keep a copy outside of strive). There are also some files which are not part of the base game which reside only in the roaming/strive/mod/AricsExpansion folder. I think the only file in there that is modified is expansion.gd.
So, for base game files put the code into the files located within the main game folder. For expansion only files, put them in the files in the roaming folder.