You can set how long a booking normally lasts for each room / area. On the terrace, for example, the average may be 60 minutes, while people usually sit for longer in the dining room. To change the length of stay, click on the cogwheel at the top right and then on Manage rooms & tables, as shown below. You can then edit the desired room and set the average booking duration.
You may deviate from the standard for each stay by changing the duration when creating or editing the booking.