The Replicator's feed tubes lie along the back of the Replicator, but the filament feeds from spools that stick out from the back, especially the left extruder spool which is pushed out 20 mm. So the filament can bind getting pulled across the spool, or even occasionally wrap between the spool and the Replicator. This support bends the feed tubes out so that they're centered over the spools, causing them to feed more smoothly.

Make sure that the Replicator's feed tubes have a few inches of loose tube below the clips. If yours is not like this, you may need to unclip the clips and reclip them to the tube.

Print. 10% fill, one shell, is fine.

Move it 200mm in the Y axis (i.e. from the build platform to the back of the Replicator).

Slide the support under the three cables on the back of the replicator, and position it so that the left extruder's feed tube slides into the shorter slot, and the right extruder's feed tube slides into the longer slot, and the black cable runs through the middle. Rotate it up so that it stands straight out the back of the Replicator. The (black) center cable should move freely, and the two (white) feed tubes will squeeze slightly into the slots. The pressure from the cables will hold it in place against the back of the Replicator.

The attached picture should make everything clear.