I tried to split my game into several smaller resource packs and load them in the background, but how do I load them? I only know how to upload local files. When I export and post it on a website, I don't know how to load it in the background.
Maybe you want to use preload? Or do you want to load files that are not packaged as part of the code at all, maybe look at https://docs.godotengine.org/en/3.2/classes/class_file.html
Edit: Or click the link with suggested answer, which covers resource packs that are loaded in the background :)