Hey there,

When someone purchase your project, they will have access to all assets that do not have a custom price set. That means, if you upload multiple files, and do not set a custom price for any of them, and user that buys (or has already bought) your project will have access to all of them.

Or do I have to use the butler? (I understand that it is used for games and not for assets, but I could be wrong)

You can use butler for anything, it is a tool that you can use to upload files on a project. It’s a command-line tool, so there’s a chance it’s easier to use for programmers, so it might not be as popular to non-programming related projects.

Hope that helps :)