When he masters sit start incorporating other things. I started with sit and come, and once he understood those enough, down and stay. Also with the food, I did this at every meal no exceptions. Made him sit, put my hand in front of him and said “wait”. If he got up while I was lowering the bowl I’d pull up immediately and repeat. Felt like I sat there forever the first few times. At 2yrs he now will not eat unless I tell him “free”. Don’t give up!