She needs a nest (even if it's just a cardboard box turned on its side), with suitable nesting material.
She needs shelter from the weather (heat, wet, wind) and protection from predators.
She needs food, water, and enough space to stretch her legs and poop.
She does not want any other chickens bothering her, so a pen of her own can be good.
You do not want other hens laying eggs in her nest, because they would develop later and hatch later, and that gets difficult to manage.
If you want to move her to another nest, do that before you give her any real eggs. Just move her and provide fake eggs for a day or two, until she is settled on the new nest. Some hens are content to sit wherever you put them, some refuse to sit anywhere but the nest they chose, and some fuss for a bit and then sit where you want them.