A very big one. Both front seats, the rear seats, center console all have to be removed. Then, you will have to pull the carpet up with some force since it is glued down. Replace the padding if it is ruined (100% chance it is).
After that, lay in the carpet, but make sure you use spray adhesive to keep it down. Line up all the doo -dads and replace the interior.
All done... Good luck!!!