[All] End Condition Target: Elevation - How does one use this?

I'm trying to grade a pond adjacent to a road. The drainage guys gave me the pond bottom elevation and I have a 3D Hinge Point. I wanted to simple run a Linear Template along the hinge to locate the bottom along that area. I say that End Conditions have a Target Elevation mode. Once Selected, there is no location to identify the elevation to target. I tried creating the linear template, assuming it would ask for the elevation during placement, but no prompt appeared.

So now I have a linear template created, but its not displaying anything.

The Help file is no help.