I just did this, so you’re getting great advice. At one week of age, remember, they need to eat every 2 hours, and clean them at that time. They will probably pee every time, but poop, maybe not.
To eliminate, I used Puffs Plus with lotion, and those pure cotton make-up remover pads. Even so, they still got diaper rash; I put some petroleum jelly-based diaper rash salve on them and that helped a lot.
To keep them warm - I put mine in a soft-sided travel crate, on top of a towel, and under that I had a heating pad set on the lowest setting. They also had a Hot Hands pack at one end of the crate they could snuggle up to if they got too cold.
If you find feeding with a syringe too hard (I can’t do it), use an eyedropper for now, until you get them on the bottle.