Infant car seats & taking home babies?

Hi ladies, I will be a new mom to twins and I would like to make to best decision when bringing home the babies. I picked out a twins carriage and car seats. I'm a little confused how I will take them home. Do I purchase car seats that go along with the carriage and use them as a carrier ? What's the best solution? I don't extra things that I will not use or need at this present time.