Feature disabled until a better solution exists

Watch the video if you haven't, only use this resource after watching the video

Here is a link

Open the Animation Blueprint and select the Foot IK Node

This will allow you to begin setting up the Foot IK clipping area as well as the extents.

Full Image

0.001 Always on the Vertical Box Dimension

This prevents the box lifting the foot off the ground; effectively you are making a plane around the base of the character's foot

Use the skeleton to adjust foot_ik_center sockets

This will allow you to position the box/plane to center it properly on the character's foot. Remember to keep it at the very base of the foot so it doesn't offset the foot vertically.