The second doesn't sound natural

Here are a few subtle differences. I will buy you a new car when you finish your schooling. (This usually meaning graduate from high school or university.) I will buy you a new car when you have finished school. (This also usually means graduate.) or I will buy you a new car when you finish the (this) school year. (This usually means finish the present year, but returning the following year.) Hope this helps

2) I will buy you a new car when you have finished school(I find it more natural than the first sentence)

I will buy you a car when you finish your school... (This mean around the same time...sounds a bit strange) second option also possible but without will. 2) I will buy you a new car when you have finished school.(this one is more correct...as far as British English is concerned)

Артем вы неправильно прописали when u will have finished мы не употребляем будущее когда мы говорим when