iCandy Double Buggy

Hi all 😍 we have a little baby girl due at the end of March. We also have a gorgeous little boy who will be 18 months old, we're crazy, I know 🤣 Anyway, to the point, buggy wise we have an iCandy Peach 5 and I'm just looking at advice on how to change it to a double buggy. I've emailed iCandy and their Facebook page and really not recieved the best help. We'll need the seat and car seat option. Just don't know what we need to buy to adapt it. Can anyone shed some light please?