Programming doesn’t work.

Just started Robotics Smart Machines Rovers & Vehicles by building the turtle bot. A good starter. Moved to programming on page 8 of manual using Program 8 as outlined. The “GO button” does not work. We cannot get the program to function. We are using a 6th edition iPad with iOS 15.2 with 32 GB ram. 
can you please help?

Thank you in advance for your assistance. 

Lorne Heslop