Asus M3A - Motherboard - ATX User Manual page 31

2. Attach one end of the retention bracket
to the retention module base.
3. Align the other end of the retention
bracket (near the retention bracket
lock) to the retention module base.
A clicking sound denotes that the
retention bracket is in place.
Make sure that the fan and
heatsink assembly perfectly fits
the retention mechanism module
base, otherwise you cannot snap
the retention bracket in place.
4. Push down the retention bracket lock
on the retention mechanism to secure
the heatsink and fan to the module
base.
ASUS M3A 2-9