@shaz7 You can wear one and carry the other, or double wear (which I did in a moby wrap when they were that small). Mostly though, moving one at a time was the way to go.
I did eventually get used to picking up and putting down a baby while I was holding the other, but when they were so little and floppy, it made me nervous. Sometimes I would slide an arm under each baby, cradle their head in my hand, and then lift them both up onto each shoulder, but doing this only made sense if I had another flat surface to lay them both down on (like moving them from one spot on the floor to another, or just picking both up because they were both crying).
As a safety note, we wouldn’t carry both twins up and down the stairs without a hand free - just too much risk of slipping and having all of us tumble down the stairs.