If you were prompted to 'Notify' your company contact and received your authentication code, select 'Complete Registration' when you open the mobile app again.
Or if mobile app screen is still up, you will see the below image and will select 'I Have Authentication Code' to proceed.
Next screen is where to input the authentication code received. The code sent to you doesn't expire. You may request another code, once the time has counted down the option will appear to request another code be sent.
It is not recommended to use the 'Start Registration Over', unless you know the information you entered when registering was incorrect. Starting your registration over will require a company contact verify you again. At that point any previous codes sent would be invalid. You would need to wait on the notification contact to verify you before you would receive a code again.
Click link for view of verification section - Registration