Take care to not let the tail gate fall on you as the lifts are removed. Have a helper hold the tail gate open, or use a secure method to hold it open.
Using a screwdriver (A), lift up slightly the socket clips (B) of both ends on the lifter (D), and then remove the lifter from the bracket (C).
Install in the reverse order of removal.
Make sure the tail gate locks and opens properly and locks securely.