How can I enter individual contributions to a second HSA, not through my employer? I didn't receive a 1099-SA for it because I didn't take any distributions. Where in TT?

I can't find a way to list a second HSA if I didn't receive a 1099-SA. I can't even find a way to pretend that I made additional post-payroll contributions to the first HSA rather than the second HSA. I want to get the tax break from this contribution but there's nowhere to enter it.