Hard to tell, but it looks like it had black tip and then maybe too much water at the root zone since it wasn't leafed out. If it's not too desicated, you could try to cut off the lower rotted portion, let it dry for a week and then try rooting again. Make sure to put it outside where it is warm, but protected from rains. It looks pretty shriveled though. Maybe others can help more.

If this was mine, I'd cut off the bottom rotted portion (cut until you don't see anymore brown rot inside the trunk). I'd do the same with the tips, cut down until you see healthy tissue inside. Dip the cut bottom into rooting powder, let the branch dry for 1-2 weeks, then plant in fast draining soil and set it in a warm place. Water only once when planting, then don't water again until leaves appear.
Good luck!

What should I use to cut it? I'm not a plant expert, this is my first attempt! :)
And rooting powder can be found at Lowes? Thank you!

I'd just use a pair of garden shears (clean blades with alcohol). The rooting powder ("rooting hormone") can be found at any Lowe's, Home Depot or Armstrong where the fertilizers are.