Please, absolutely refrain from using moss for Dendrobiums. It retains way too much moisture for Dendrobiums.
Most Dendrobiums are epiphytes (grows on trees) of trees that are usually barren of moss. Instead of moss, most of these Dendrobiums are growing on trees predominantly covered by lichens.
Yes, there are some Dendrobiums that grow on trees that are covered in moss.
There are even Dendrobiums that grow on rocks.
For the sake of simplicity, yours is a man-made hybrid that most likely has parents that grow on trees without moss.
Here are some links to some photos that are a perfect example what I'm talking about
:
http://1.bp.blogspot.com/_ZvzX7o1KAy...ii+in+Situ.jpg
http://www.orchidspecies.com/orphotd...dfalconeri.jpg
http://3.bp.blogspot.com/_mXGRNKBlVq...0/HPIM0526.JPG
http://www.orchidspecies.com/orphotd...draphyllum.jpg
Please find yourself the smallest pot that will snugly fit the root mass, that you can find and put it in there. They like to be grown a bit potbound.
I'll be dead honest...
The roots are probably mostly dead as a result of that moss, and the chances of it recovering is very small. It's not to say that it will not recover, but don't expect it to. If it does, at least you didn't get your hopes up and therefore you won't be disappointed, and perhaps even be pleasantly surprised.
Other than that, it's also probably not receiving enough light for it to bloom.
Dendrobiums grow best in moderate indirect bright light.
It also most likely grows intermediate to warm (50 F to 90 F).
They like 50% - 70% humidity.
If I may make a recommendation...
For a person who is first starting off with growing orchids, I think it would be to your utmost benefit to buy strong healthy stock to limit the amount of headaches you will encounter down the line.
Even when you decide to buy healthy stock, there will plenty of room for mistakes and learning.