Installing the trunk divider panel, push in or clip held?

[WH23G3G]

I've pretty much got my trunk all done and jammed out back to the original color, my fresh bumper, tailights installed. I've got a cardboard trunk divider I bought from Year One correct for the 73 model. I haven't even opened it or the trunk mat. How does the trunk divider panel go in? Is it held in by clips or just pushes in? I haven't even opened the trunk mat. Is it already cut for the trunk pan or do I have to cut it?

[Nacho-RT74]

divider is held by the back seat hangers