Curiosity Stream

I just came back to Xfinity tv a few days ago, after trying just streaming channels for awhile.  While I was still doing that, I recently signed up and paid for a year of Curiosity Stream.  Now, other than subscribing through Xfinity, I can't find any way to get or access the app.  Why is there no CS app or way to sign on through my own pre-existing, direct CS subscription?