Does the Box 12 amount have a Code D, a Code W or do you have an amount for both codes? Code D is for a contribution to a 401(k), Code W is for a contribution to an HSA. You can verify the entry of your W-2 is correct in the Job section of Income & Expenses.
Once you have an amount on your W-2 Box 12 with a Code W, that will automatically be entered as an HSA contribution. You can then enter any additional information about your HSA, including additional out-of-pocket contributions and withdrawals by going to Deductions & Credits and scrolling down to Medical, and clicking Revisit/Start next to HSA, MSA Contributions.
