Your self-employed health insurance deduction cannot exceed the amount of the reimbursement from the S corp for healthcare, reported as wages box 1 of your W-2 from the S corp. The deduction goes on Schedule 1 line 16, which TurboTax will do automatically when you enter the Schedule K-1 (Form 1120S) from the S corp and indicate that you personally paid for healthcare and the S corp paid you wages.
