Anubias nana is a very slow grower but is almost impossible to destroy. I know it was my very first plant. In that case, just put it somewhere where it can get a little bit of sunlight (not too much) and keep it with some fish. Just feed the fish and change the water occasionally (like once a week). Eventually your anubias nana will start sprouting new leaves. Don't try to force growth through high light, long lighting schedule, and fertilizers. The only thing I might add is a little KCl or salt substittue for KCl which is the only thing that might be lacking from fish food or poop. It doesn't matter if you tie down to rock or wood. It's just to keep it from floating which you can also do if you want.
JUST REMEMBER IT'S A SLOW GROWER. IF YOU HAVE ANY DOUBT, LEAVE IT MORE IN A SHADED AREA. IT WON'T DIE FOR LACK OF LIGHT SINCE IT WILL JUST GROW SLOWER.
I've kept one in a tank I neglected for over 8 months. After everything else turned into brown mush and disintegrated it was still there along with my phillipino java fern...
