Asus AP2400R-E1 - Manual (Page 30)

Chapter 2: Hardware setup 2-16
5. Place a hard disk drive into the
drive tray, and secure it with four
screws (two on each side).
6. Carefully insert drive tray and
push it all the way to the depth of
the bay until just a small fraction
of the tray edge protrudes.
7. Push the tray lever until it clicks,
and secures the drive tray in
place. The drive tray is correctly
placed when its front edge aligns
with the bay edge.