I tied it to some small bit of mopani.
And dropped it in the front of the aquarium where there is lots of light.
I got it in my Â£3.99 pack of 25 plants from last-trading-post and I think they put it in by accident since it says nothing about mosses in the description.
Is it java moss? On looking at different sorts of mosses I've found that they all look pretty much the same :S