First, if you are wondering where to find/enter the HSA contributions you made, normally it has already been reported in Box 12 of your W-2 with code W: Employer Contributions to Health Savings Account.
NOTE: If you made HSA contributions not reported on your W-2 (this is uncommon), the TurboTax software will ask about that when you step through the Medical section. Look for the questions Were HSA contributions made in 2016? or Do you need to make any adjustments to your HSA contribution amount? Answer Yes and we'll open a screen where you can enter that information. More details here https://ttlc.intuit.com/questions/2766470-where-do-i-enter-my-hsa-contribution
Secondly, if you just need help figuring out how to fill out the Box 12 sections from your W-2, in the TurboTax software; see instructions below:
https://ttlc.intuit.com/replies/4785646