[Koha] Koha - item - Restricted access

Hello! A bibliographic record has been made. The item (donated from a private collection, has marks) is access to a limited circle of users (university employees). The item has a restricted access. The librarian herself decides who to lend and who to refuse. When trying to checkout this item, we receive the message "Item is restricted". What needs to be configured or corrected so that this item be able to checkout when it is necessary? Good Luck! Igor A. Sychev Tomsk Polytechnic University https://lib.tpu.ru