If you want it to be compact, cut off the trunk just above the 4th branch (1st branch on the right as pictured). Cut back all the remaining branches to the most interior leaf, or to a point with leaves that you like the look of. Put the tree outdoors in full sun and water every day it doesn't rain. In the future, keep branches/stems/twigs compact by clipping off the lead leaf/bud and one or two more leaves towards the trunk any time the stem exceeds the canopy boundaries you have set in your mind's eye. Occasionally, it will become too crowded in the interior, thin by removing crossing branches/stems/twigs in favor of those that are attractively arranged. Remember that it will re-grow something, somewhere in response to anything you remove, so even when you do it wrong, -and learn what not to do, it will forgive you.