It is really simple to check out a few appointments at once on the appointment screen. To do so just follow:

1. Click once on the first appointment on your screen to make the edges yellow.
2. Hold down the Shift key on your keyboard, it is here:
   
   
   
   
3. Whilst holding down that button, continue to single click on the appointments you wish to group together. Then hit Pay.
   
   
   
   
4.  The system will then bring you to the checkout screen where all 3 will be added. Don't panic if you accidentally clicked one. In here just delete what one you don't want anymore
   
   
5.  Select what payment method they are paying with and you are good to go.