Gateway 8400 - Manual (Page 23)

18 Installation
5 Press the latches on both sides of the system drawer side rails, then push
the system drawer back until the inner rail spring latches lock.
6 From the back side of the cabinet, release the spring latch on the inner
rail while pushing the system drawer to the back of the cabinet.
The first time the system drawer is pushed back into the cabinet there
may be some restriction of movement. The drawer should move
smoothly, without binding or restriction thereafter. If there is still
restriction of movement, make sure all rails and brackets are aligned
properly.
Cabinet
mounting rail
System drawer
side rail latch
System drawer
side rail