Hi @Kathleen382 ,
did they confirm or tell you that they couldn't see check-in instructions or are they just unfamliar with using AirBnb website and app?
By coincidence I have an upcoming trip myself and today, a week before, I got the first reminder from AirBnb about my trip. The email also includes a link to the check-in information. The link is only available three days before the trip. I'm sure that there comes another reminder.
I have the impression that some guests do not actively access the information we store in the app or on the website.
To ensure that guests receive all the required informacion process check-in correctly, it might be useful to share the information through the app. In comparison to the website you can use it to send documents, i.e. pdfs, and photos.
Creating a video might be useful, but keep in mind that it always has to be publicly accessible. Would be even better to make it downloadable, because you never know if guest have internet access when checking in.