Last step is to reconnect everything in the reverse order you took it apart in.
Once x-pipe is up in place, tighten all the bolts
Re-attach the O2 sensors, making sure to tuck the wires back in their holders
This is a good time to fire up the car and check for exhaust leaks
Attach metal skid plated under engine
Re-install heat shield under transmission
Re-install felt pieces in front of car under bumper.