So I got TWO anubias Nana plants. They have roots, but also have a rhizome. Could I burry the roots and keep the rhizome out of the gravel or should I just attach the entire plant onto a piece of driftwood that I have?
Either way works. As long as the rhizome isn't buried its good to go.
I myself like the look of the roots so I keep mine tied to driftwood. The roots make it look more realistic. Some don't like roots to show so they hide them.
Either will be fine. You can bury the roots so long as the rhizome is not buried. Or attach it to something. Personally I prefer just to weight mine down with a bit of lead ribbon until the roots dig into the substrate.
I had the same problem, I wedged them into the approximate postion I wanted the leaves to be with a lead weight, the roots grew onto the driftwood rather quickly and they plant is doing quite well now.