The dishwasher has a small cup in the corner

Delete the cap or cover on the small cup.
Spill liquid soap directly into the port.
Avoid overfilling to prevent spills.

For Air Gaps:
Make sure the gap is clear of debris or blockages to maintain proper functionality.
If water spills over, it leads a clogged dishwasher drain that needs cleaning.
Why Is It Important?

Convenience: it saves time and avoids the hassle of accessing the underside of the sink.
Health and Safety: it secures proper drainage, maintaining a sanitary kitchen environment.