You can add musical instruments to the catalogue of the library system so that they can be loaned out as and when needed. As these are physical resources they need to be allocated a barcode, but you would probably prefer to attach the barcode to the case of the instrument or the accompanying documentation rather than the instrument itself.
From the New Resource screen, click on the 'Musical Instrument' icon.
Add the barcode and the ISBN if it has one and click 'Continue'.
Once the resource record card appears, click in each field and add information as required. Some of the boxes will allow you to select from a list of previously entered information, the rest are free type fields.
Click 'Save' to add this resource to the system.