There are buttons for the Play Store and App Store halfway down. Its under the heading: "A very first build, limited by (play & i) stores"
And the homepage says in bold letters “The PeerTube mobile app for Android & iOS is out!” but it’s not a link! There’s a link further down but it goes to this article where you then have to scroll.
Not every site has to be super conversion optimized but it’s just common sense to put a CTA at the head of an announcement. joinmastodon.org gets it!