First, remove the front sight. Remove the magazine cap screw while preventing the cap from launching under spring pressure. Remove the front and rear barrel band screws and slide both bands forward off the barrel.
Tip: Put a few drops of oil around both bands to ease disassembly and help prevent finish scratches. Pull factory forend and mag tube off rifle. Install the new M-LOK forearm and barrel band. Put a drop of blue thread lock on the band screw threads, install the screw through the existing crosspin slot in the barrel, then gradually snug the screw while keeping the band indexed on the receiver. Reinstall mag follower and spring, then front barrel band and magazine cap.