At the header, the driver side bolts right on, on the passenger side you use the supplied gasket to ensure a tight seal. Use two small rubber bands to hold the gasket in place. Finger tight the bolts to hold the front part of the h-pipe up to the headers. A shows the h-pipe hanger. It's two rubber pieces attached to the tranny.
B shows the h-pipe at the muffler tubes.
C shows the new pipe on the ground. The Pro Chamber in place. In the rear mate the h-pipe end with the muffler tubes and finger tighten the bolts. Once everything is hanging, you can fully tighten the whole system starting at the headers on-back, while holding the pipe in place for chassis clearance. Pro Chamber and cat-back.