Hello TheBlack...
I weigh my driftwood down with rocks, but there are other ways. I've also used black sewing thread and wrapped black suction cups to the wood and secured the cups to the glass. Then, planted Crypts around the cups to hide them. By the time the sewing thread disolves the wood piece is waterlogged and stays at the bottom.
Another option, I like is to drill holes in the wood, attach Java fern to the piece, again with black sewing thread and just allow everything to float. Attached is a pic of a 45 G tank I use to experiment with different substrates, liquid ferts and anything I find. I floated some Java fern in it and it grows very well in low light.
Just a thought. Above everything else, have fun!
B