A shelter made like an A frame from ply or even pallets braced together is enough at this time of year, a shelter really, so long as your place is fox proof, they grow quickly you'll find and like to huddle together so a trug bucket (large-ish base) gives them enough room to move around in for the first week or two and feel secure. Speak to them lots and they'll get to know you quickly.
Our geese free range over 5 acres and wander a lot at this time of year, the females wean themselves off the group gradually by sitting away from them for a bit then rejoining the group and eventually this leads on to egg laying on a nest which takes about 2hours per egg. That's our geese, don't know about other people's geese.
Geese are great and troublesome in equal measure I think, I love them, my son thinks they look like miniature brontosauras wandering around the place with their slow walk