As you can see, if you are using the default role, you can leave it alone, it is configured with a footprint by default.
DecalMaterial:Decal material for footprints.
Decal Duration: How long the footprint decal will be displayed.
DecalFadeOutDuration:The time after which the decal fades out (after being shown).
Decal Size:The size of the decal.
CustomFootstep Decal Details:This is where you can fine-tune the effect when using your own decals.