How do I discipline this child?

[Discoveries]

It could be a few challenging weeks ahead, if not more.

For toy taking I would remind that we do not take toys that someone is playing with, and maybe suggest a few options. Should it continue, I say that they seem to be having trouble picking something to play, so I guide them to something to play letting them know that I will make the choice for them, as they keep taking something from someone else. Next offence I'll remind to pick something someone else is not playing with, or I will pick for you.

If he is playing rough at the train table. I would model playing nicely with someone. If he was struggling to play nicely then he would be guided away from the table to find something else to play.

Yelling, would be a constant reminder we use our indoor voice and nice words here with friends. In this case I wonder if he is modeling words he has heard often elsewhere. If it was a constant disruption for the meal, I would excuse him to finish eating up elsewhere on his own.

Before going outside there would be a reminder about not throwing sand in the sand box. First offence results in being excused from the sand box for the remainder of the day. The lid, I would set up so breaking it was not an option.

First stomping of chalk, would be a talk on playing nicely with our toys and things. Second attempt would be since you are not listening or playing nicely with the chalk, you are not to touch it anymore today.

Aggression would come with a chat at the very start of the day and cover pushing, hitting, kicking, throwing stuff at others etc. It is okay to be grumpy, sad or whatever feeling you are feeling, but it is not okay to hurt anyone here ever. It looks like repeated acts of aggression without remorse are an issue, so he may need to be your shadow at all times for a bit, to keep everyone safe until he learns to play nice.

If there is little correction at home for similar behaviors though, it may take awhile to get results. It can become unfair to the group as a whole to have so much attention focused on one to keep the group safe and happy.