Problems with Uber app. Help!

I have only taken 3 trips as a driver.  All 3 times, the app would not acknowledge that I had picked up the rider--navigation kept telling me to go back to pick them up again and would not show me their destination.  I had to end up cancelling all three trips because it would not move on.  Do I need to do something or click something to indicate that I picked up the rider?  I have an iPhone 12.  Thanks!