Step-by-step guide

1. Double tap on a any blank slot on the appointment screen
    
2. Search for the client's name and select it
    
3. Now tap on the History button at the bottom of the pop up screen
4. A client's future appointment will appear highlighted in green at the top of the history list. If the client has lots of future appointments - they will all be grouped in green at the top of this list.
    

5. ps. You can also find a client's future appointment by going to the Clients section and searching for a client and then tapping on the Service History tab.