Good question, and yes. It is somewhat complex. For the general process of preparing data for import, I suggest you look at this user guide (it refers to User Admin, not Library, but the principals are the same): https://gibbonedu.org/support/administrators/importing-users-into-gibbon/
The complicating factor for the Library is that the import format is different depending on the type of item you are importing. If you can let me know the type of object you are importing (Print Publication, Computer, etc). I can create a sample import file, and some documentation for you.
Please can you share the CSV sample (and possibly some documentation) for import of Library items for following Types:
As always, thank you.
There is a guide on the import page (Learn > Library in the main menu then Import Records in the module menu. It shows you which fields to include. If you want to build an import, we can check if for you if it does not work. You might also want to look at some of the general import information in https://gibbonedu.org/support/administrators/importing-users-into-gibbon/.