You can migrate the entire folder if you want, that would be a lot faster
In the sample project, right click on any asset or folder in the content browser, and choose “Migrate”, you will then be asked where to migrate too, and in there just choose your projects “…\Content” folder, any other folder will give you an error.
Also, you can use these assets in your game, all assets available on marketplace so far can be used in your game no problem. may change, but they said it would specifically state that you cannot before you download if is the case.
I am not sure about the option too cut/paste into your folder, but that may also work, if not you might have to import it, but I’m not entirely sure about method, so don’t quote me on that! 