How many Ultrasound & doc visit

So i had my 1st visit today and i go for my 1st ultrasound at 21 weeks and my next doc visit at 16 weeks. They said I wasn't a high Risk even with a premature set of twins and hemorrhaging with my last baby. I'm just confused how this twin prenatal care visits are supposed to go. The clinic I went to with my last twins closed down and I saw them twice a month and they did a scan once a month.. ** anyone have a general idea of how this twin prenatal care visits are supposed to ggo and be classified*** thnx