It won't do anything until spring. I have eight and they're all dormant for the winter. Your paperbark should be waking within the next few weeks starting with swelling buds into the years' new leaves.

I do not believe that it is a good idea for the tree to be on a heated porch. The heat may fool the tree into coming out of dormancy early that may have some negative effects on the tree in the long term, but of course I live in zone 9a, so you may have a different situation. You can get additional info from following posts.

Well, first of all by heated sun porch are you referring to an enclosed area? Because if you are, I would recommend putting the tree outside where it can get winter rest. Maples are particularly finnicky about missing winter and they will definetely die if they miss to many...probably.

However, it has probably gone through a long enough dormant period this year if you recieved it recently. If it is indoors and is keeping above about 50 degrees with sunlight I see no reason why it wouldn't begin to leaf out.

However, It takes about 2 weeks for most maples to begin budding and leafing out after being brought indoors (with light of course). I've never tested this time precisely with acer griseum, but I'd assume it is similer to others.

Sorry if I made no sense, my mind is a wandering a bit today.