If logged in as the administrator / moderator, you'll find the Make reservation link in the top-right corner of every ibookfishing page. As the administrator, you won't have to fill out the required fields such as email address etc.You can also immediately mark the reservation as confirmed.
Please note that if you don't know or want to enter ANY details (such as name) it may be better to simply mark the period as vacation. This will make the resource unavailable for reservations in the given period (vacations can also be labeled, e.g. 'reserved for family').