Carefully slide the plastic housing of the antennas (the back cover of the router) up and out of its slot.

You may need to move the motherboard at this time in order to giggle the antenna's housing off.

Be sure to remove the cable connecting the motherboard and the antenna from its holding compartment at the right edge of the router (See image two). Pulling on either the motherboard or the antenna's housing while the cable is still secured may damage either or both components.