Removing them...
All you have to do is remove the snap covers to the storage compartments. Inside on the forward end you'll see 2 nuts which need to come off. Careful, because these hold the front (painted) "dome" on to the upper half of the lowers. Be sure you hold onto this dome as you remove the second nut. Then at the bottom of each lower is a torx head bolt that holds the bottom of the lowers to your crash bar. The nut on the other end of this bolt is a nylon locking nut, so you'll need to use the appropriate wrench on it.
That's it, just three fasteners on either side, and your lowers are off.
Reinstalling...
Take note that both the lower and upper mounting points are somewhat "variable". That is to say that you should loosely mount the upper two bolts, then loosely mount the lower bolt. Adjust both sides (both lowers) so they are of equal distance from the center mounting bolt on your crash bars , then tighten your nuts/bolts down. Be careful not to over tighten them, you don't want to break the bolt mounting points .