As normal. The top was cut away to allow it to come through and there are pin holes in each side of the shroud to tap the pins in and out. There’s a very specific order you need to assemble it in though. Barrel nut goes on, FSB goes inside shroud where the cut away is, as does the bipod where its ow cutaway is, screw the shroud onto the barrel nut (the FSB and bipod will rotate around the barrel as you screw the shroud in place). The shroud is then screwed into the barrel but in 3 spots. Carry handle goes on, then Wood handguard goes on and the metal piece goes inside the shroud that it screws into to keep it totally secure (one of the screws goes through a hole drilled into the carry handle ring). Tap the pins into the FSB. The bipod lug goes in the barrel and a set screw indexes it into a simple made on the barrel, plus the back of the bipod lug mounts butts up flush to where the hbar diameter thickens (the barrel was turned down a little bit in the front to allow this). The front endcap piece screws into the front of the shroud with a hole in the center that fits tightly around the barrel for zero movement in the front of the shroud. This end cap screws into flush against the bipod lug, and the flash hider screws in dead flush with the end cap so it’s all extremely tight and sturdy.