I carried for just the first few days while Luna became settled into her new home, and accustomed to the crate. However during this time I also kept a leash on her whenever she was awake and up.... very lightweight and the handle cut off, so it couldn't snag on anything.That way she could get used to a leash, and it was useful for grabbing to stop her from getting into trouble.Within a few days she was quite happy to be gently led around by the leash, and it meant that I could choose the spot where I wanted her to potty, and make sure to always go back to the same spot, to re-enforce the habit, and being led by a leash limits the distractions on the way.
I liked her to walk herself, and we always used the same door and took the same route through the house .... I just feel that her taking the steps herself imprinted it better, but that's just my own feeling.
I didn't do the bell method as we have doors wide open all the time, except when we sleep at night. So my dogs are all 100% house trained, but have never actually learnt to ask to go outside, as they can just go !