You might ask her to check her emails to see whether she has the confirmation there, and whether the link in the email takes her to the reservation.
But I think the guest will likely have to call Airbnb, @Anne1627 . If the email advice doesn't work, this isn't something you can help her with. She might be looking in the wrong place or her browser needs refreshing or she has inadvertently created a second account or maybe there indeed is a problem with the reservation that Customer Service needs to sort for her.