Uploading Modules?

I'm in the midst of creating my first campaign on Roll20 for a group of friends. One of them has made campaigns here before and he emailed me a module to upload so I can see how he set his up. I tried dragging the .mod file onto a new campaign, as that's how I've added images to my campaign, but the app seems to freeze. I'm wondering whether uploading is a premium feature or whether I'm just messing up how to do it.

They must be using some other VTT.  Roll20 does not support downloading Games or uploading Games.

That's a fantasy  grounds file.

Oh. OK! Thanks to both of you. I checked out fantasy grounds and didn't like it as much as Roll20. Didn't realize he and I were talking at cross purposes.