I too am a stay at home mom to my 5 yr old daughter and my 2 yr old son. My daughter too started kindergarten this year.
When she was younger we had problems with her following rules and simple directions. My husband and I stayed consistent with her and our son. We put them on the wall, (not the corner) we set a timer and when the bell would ring they new they could get off the wall. We would ask them to come over and tell us why we put them on the wall, and explained to them why they are not allowed or supposed to do what ever it is they did.
When I say " stay consistent" I mean it. When we are in public I find a wall and put them on it. For example we were in Home Depot our son was not listening to me so I put him on a wall. It took 3 min. to get him to act right. You might get a few people looking at you, but it is a different look than if you child was screaming or crying.
Good luck!! Please let me know if this works for you.
Happy New Year!