Step One: Brush your hair

Step Two:
Grab a section from your hair, perferably near the front. It shouldn't be TOO thick or TOO thin.

Step Three:
Flip your section of your hair over, to the center of your head, don't let go of your hair though.

Step Four:
Repeat with the other side of you'r hair. You should have both locks of hair in one hand. I only had the one side because I had to tie my hair to take a picture, however this should do it:

Step Five:
You have both locks of hair centered at the very top of your head, like this:

Step Six:
Take a hair tie, or scrunchie, and make a bun with the hair you have, it should look like this:

AND TADA biggrin
You now have Ursa hair, but don't forget to top it off with a ribbon or hair accessory, to hide the scrunchie and ready here's Ursa biggrin

I don't own that picture either, I give credit to the creators of Avatar, and whomever made the picture