It's dead easy. You open an account and start uploading whatever you like.
You have 1GB of storage (as far as I see it, this is rather generous for a peertube instance), which is not too much, but enough for a number of videos.
Right now, I have 16 videos online which take about 650MB, but for the most part, it is the 45 minutes video by Cory Doctorow, which I will take down, if needed.