Blocking a time slot

From the daily view of the back-end calendar click over a row corresponding to the desired hour you want to block, click on " Block" button then select another row corresponding to the ending hour of the slot you want to block then click on " Block these rows".

You'll see these rows became grey as they are not more available for new reservations on front-end booking form.

To "unlock" and make them available again just click on " Unlock this row" button.