One of them will need to create an account, @Mandi22 . I know you know this, but just making sure: third party bookings are not allowed.
Then they will do what any of your guests usually do. They will look for a place within their budget and in the area they want, and book it. As first timers, they may have to send a request, but most hosts will be happy to take travellers who have a good reason to be in the area and who will be out and about all day.
All the best to them!