As an owner (or as a renter) there is nothing to be done by you to close a booking. This will be done automatically for you within 2-3 days following on the end date of the booking! The owner receives the earnings of the booking within a few business days and - in case a deposit has been paid by the renter - the deposit will be reimbursed after appr. 1 week. Just make sure that your IBAN has been filled in your Gearbooker account!
Also, after a booking has been closed by the system, both renter and owner will also automatically receive an invite to leave a review about each other and about the equipment.