For directories, it’s permission to cd into it. Read is whether you can list files, and write is remove, rename, or create new files. Don’t ask questions about the secret sticky bit
It’s obvious you are an independent author of D&D materials with a desire to contribute to the community.
At the same time, it would be nice if you noted anywhere in the post or especially the title that you are advertising D&D materials for sale. It’s fine if you make money off your creations, but irksome when it’s not clear that it is advertising, and also when any post perpetuates the idea that D&D is the default, or only, system.