The external access QR codes are associated with individual Premises and not Organisations so the set up page is accessed through the Premises menu. Select Manage > External Access to bring up the setting page. Details of each of the functions of the External Access can be found here Using External Access (QR codes)
When you receive your QR code(s) you will need to assign them to your premises, if you haven’t received your QR code(s) you can order them (available here) . Please follow the steps below to assign them to Premises.