You can import libraries into your Fusion hub from local .lbr or .flbr files.
In the upper left corner of the Fusion window, click Show Data Panel
to open the Data Panel.
Select the project into which you want to import the library, and double-click to open it.
In the Data Panel, near the top of the panel, click Upload to open the Upload dialog.
In the Upload dialog, click Select Files, then browse to where you have stored the library or libraries you want to import.
Select the appropriate libraries, then click Open to return to the Upload dialog.
In the Upload dialog, note the import location, and click Change Location if you want to select a different project or folder.
Click Upload to import the libraries and close the dialog.
.lbr files this way will break the link to Library.io and any unsynced changes may be lost. Instead, use the Import EAGLE Libraries function in the Library Manager.