Are you looking for a run and a hutch?
A guinea hutch is ideally off the ground to protect them from damp. Position it out of draughts and protect from inclemant weather (you can get waterproof covers)
Their run should be open on the base (they don't like walking on chicken wire or mesh) and unlike rabbits they don't dig, so you don't need to sink it below grass level BUT you need to protect against anything getting IN (foxes , cats) and your pigs escaping. We have a metal run from BunnyBusiness on Amazon, it has tent pegs to secure into the ground.
It needs to be moved around to fresh grass , so it's best to have a seperate one.
Rabbits need 24 hour access, guineas need fair weather grazing.
My boars have an old wooden playhouse , modernised into Pig Accomodation (it is raised slightly ) so when the garden floods , they are safe.
Size wise - there's a website that recommends 1.2 sq metres for 3 pigs .
( I have a 2'x4' indoor winter cage that my 2 boars are judgey in, so we got a flexible fence system that gave them over 3'x5' that they were happier in) I have a shelving unit like C&C from Costco that might get used as a pig pen some time (have a look on the C&C website, really good ideas) 
Best bet is get the biggest you can. There are minimum sizes but they really appreciate more room. We give ours a Hop In tunnel in the Pighouse and the run plus boxes, a hedgehog house, wooden house. They love them, keeps them active and protected.