Try this:
Looking at the unit from the front, flip the unit on to its LEFT side. The RIGHT side will now be on top, turn the unit so you are now looking at the bottom (still with the RIGHT side on top). You should see two stand offs near the top edge of the chasis. There are two screw/washer assemblies that fit into these stand offs, they should have come in the box in a bag with other screws for the rack mount method. Once you have installed these screw/washers, you take the unit and place it on the wall bracket that you should have already placed on the wall. There are two slots on the wall bracket that the standoff screws will slide into.
I like to take a wood screw, after the unit is on the wall bracket, and install it just above the chasis. This will help prevent accidentally lifting the CX out of the wall bracket.
Good Luck.