I had to set permissions on the mods and blocks folder (if you're using the block plugin too) to 775 so that the 'select zip' works and will load in the right place. Secondly, I had to add a folder-group owner that the 'Apache' user is part of so that it would also work. Once you have the features installed, you may want to dial back the permissions again.
I added the activity to a class.
That being said, it does appear to work with version 2.6.x. Our functional folks need to now figure out how to use it within their teaching model.