I've only done a small amount of D.tube, but basically how it works is that there's a decentralized protocol happening to get all of the data up and distributed to your viewers. The upload time is HORRIBLE. But it's actually faster now that it was.
One trick that I know of for using D.tube and having decent upload time (and load time for your first viewers on the video) is to never close the browser tab you uploaded the video on. That makes it the smoothest.

As far as the best way to use it, all of your D.tube content actually just gets loaded onto your steemit blog. For your steemit viewers, they'll just see it as a regular post with an embedded video, and then there's a little meta-data tag that says d.tube. For the viewer, it will look just like when you embed your bluerocktalk YouTube videos!