Down syndrome test

Kaitlin • Wife to SB. Mommy to PB and LJ.
Hi all. At 12 weeks I'm going in to get an assessment to see my baby's risk of having downs or any other genetic disorder. Baby will be loved either way but it is something we would like to prepare for just in case. My doctor said it was 91% accurate and has NO risk at all to the baby. So it isn't one of those advanced or dangerous ones. I think it's mostly ultra sound as she mentioned I would get a nice ultrasound of baby that day that normally I wouldn't. I'm not sure what else it entails. I just know that I have to go see another doctor certified to do it and then come back and see her a couple of hours later. Has anyone had this done? What all does it entail? What should I expect? Thanks in advance!