Navdy should automatically connect to the last phone it was connected to once the display has power and bluetooth is enabled on the phone. Ensure bluetooth is enabled on your phone by going to the phone's settings, clicking on bluetooth, and then enabling it.
Tap the status indicator within the Navdy app in the top right of the screen. If it's red, your phone is not connected to a display. Click the icon and then tap the message to continue. Your display should show up in the accessory list where you can tap on your display to connect. The status indicator will change to green, and you will be able to see that you are connected to the display.
To connect your phone using the display, use the dial to open up the Quick Menu. Select Menu and then select connect phone. Find your phone in the list and select it to connect.