Like, "joinpeertube" ? The first result if I type "Peertube" on Google (I'm french, it may be different in USA).
I also think a big CTA for "Download App" would be a good addition to the credit of the root comment of this thread.
I mean, it could be a bit more visible, I guess, but it's not exactly invisible.
I get the point that maybe have browse content as the main page ... but given that the point of peertube is the network not the videoclient, the current page also makes sense to me.