Anchor both mounting brackets with a screw. (Note: place one anchoring screw on the right side of the first mounting bracket and the other screw on left side of the second mounting bracket)
Repeat this process with the primary filter.
Push the primary filter into the filter clip on the top bracket until it snaps into place.
Connect the OUT end of the pre-filter and the IN (capped end) of the primary filter with a piece of John Guest tubing.