You CAN make a library for your folder.
You almost certainly SHOULD just add it to an existing library – it will take 1/100th of the time.
Let me suggest that the easiest thing to do will be to put it in main/source/src/protocols/myfoldername and then add it to protocols.8.src.settings. That’s what we teach new students to do for quick and dirty prototyping at the Rosetta Bootcamp. IT’s not a good permanent home for shared code but for something you are writing for yourself it’s the fastest, easiest place to put it.