P-Trap installation

I am installing a P-trap in a shower floor drain remodel project and I have a question about how the P-trap should be installed.

This is a 2 inch PVC trap where one side of the trap is steeper than the other - in other words, looking at the trap from the side it looks more like a J than a U. So my question is... does the floor drain connect into the steep or shallow side of the trap, or does it matter?

I hope this makes sense.

Does this picture of a p-trap commonly used under a sink help? The arrow shows the direction of flow.

Perfect - Thanks!

trap

It should not have a slip joint in the first place, but especially if it is going to be buried