> ..I have no idea what [unzip the file] means or what exactly to do..
Ok, first off, a zipped file has been data-compressed for transport. If it's a standard .zip file, to unzip it on a Mac all you should have to do is double-click it, and the unzipped file should appear next to it.
However, if you were able to open the downloaded Logic Project, and the Save Copy As... command gave you the dialog box with the Package vs Folder option, it sounds like you must have succeeded in unzipping it (maybe it unzipped automatically on download?)
> ..[the 'package' option] for me is grayed out..
Apparently the Save Copy As... option makes an exact copy in the same format as the original, and so the Folder vs Package option is greyed out. You should be able to see if the Package option is checked even though it's greyed out, and if it is, then just go ahead and do the Save Copy As... and you should end up with a copy in Package format. If the Folder option is checked, then you might have to do a Save As... instead to save as a Project, but I'd expect whoever prepared the file probably saved it in the desired format so hopefully it'll work as intended.
But remember, after you do a Save Copy As, the open file is still the original Project, so you'd have to make sure to name the copy slightly differently, then close that original Project and open the new Save Copy As... file to work in the new Project.