Why not message Rainrescue then Janus? they need fosterers I am sure
Basically the animal stays with you and you care for it until it is ready for a new home, it may need medication, trips to a vet, help with confidence or none of these things, basically it is giving the dog a home experience.
All medical treatment will be covered by the rescue, probably food will be provided though obviously this is something that you need to discuss with the rescue. Message Rain and see where it goes if you cant get in touch let me know and I will for you if you're really interested, it is such a worthwhile thing to do, but can be hard and sad when they go.