The sat-nms RMC enclosure is DIN rail mountable. Hence simply snap the sat-nms RMC on to the rail to fix it. For plain wall mount, fix a 100 mm piece of DIN rail at the wall with at least two screws and lock the sat-nms RMC on this.
When planning the mechanical installation of the sat-nms RMC, please consider that cables to the sat-nms RMC have to be fixed o the upper and the underside. So you need some space and something to fix the cables.