You log on to the library's website "My Library" and check the records you borrowed to see if there are any CD icons in the records. If there is, just click it.

Some libraries input the contents of the CD into the library database, and then directly take the CD. If you want to see the contents of the CD, you can only consult it by the above methods.

If not, you need to explain it to the librarian at the library service desk, otherwise it is easy to have an accident. For example, the library thinks that you borrowed a CD and lost it. Check with the librarian.