@neontapir

If you just want to interact with videos on share.tube, you can use your existing Mastodon account. Try clicking on @chriswere to see what I mean. When you favourite a post there in Mastodon, it will appear as a like on PeerTube. When you reply to a post it will appear as a comment below videos etc.

If you want to upload videos to share.tube, then you would need your own account there.

You don't need to link anything.