What are the rules to table placements in cafe world?

me and my boyfriend have been playing cafe world for a few days and we couldn’t find any web pages that answered our question. what are the rules to placing tables? i know that if you have 3 sides blocked that they won’t get served, but i noticed that if it was surrounded by serving tables except one side being beside another table my person got served, and we’re confused. what are the restrictions if anyone has noticed/knows? thankyou for helping c:
if you can, please provide a picture to show us what you mean? D: