I mean, the entire setup is here in one pic (use desired channel for the trace):
Do note that the character location is around their waist, not where their feet touch the ground (at least in UE4), and traces do hit the floor. Chars are 180uus, so you may need to subtract 90 in z from the character location in the first place.
The other method is using screen-space - it’s does not care about geometry.