Ok so first you will need to go out into the great outdoors and find some branches that suit you best.
then give them a good shake to get the dirt off.

Next, place in your room where you would like for your branches to hang (coming out of corners looks good).

From there locate 2 or 3 base point on the branches to hang from.

(2 person job) have one person hold the branch in place while you eye ball from the base point to the spot on the ceiling where it will hang. Then mark it.

Take your twist hooks and twist them into the marked places in the ceiling.

take the yarn or other tying material and tie as short of long on the base points of the branches and hang on the twist hooks.

You can add jewelry to it or little diamonds for an eisley affect.