Use ‘set’ to express the placement of an object on a surface.
I set the plates down on the table.
She set the books on chest of drawers.
Important Note: ‘Set’ is often used to refer to placing plates, glasses and other utensils on the table.
Verb Forms: Set – Set – Set – Setting
Use ‘sit’ when referring to the subject which moves from a standing to a sitting position.
Can I sit down?
Please sit on this chair.