Asus RS161-E4/PA2 - Manual (Page 40)

Chapter 2: Hardware setup 2-24
6. Remove two metal bracket screws and screws on the other side of the
drive. Keep the screws for later use.
7. Pull the metal bracket to the
direction of the arrow until its
pegs disengage from the drive
holes.
8. Lift the metal bracket, then set
aside.
9. Push the drive inward, then lift it
out from the chassis.