You can confirm your shift on the Traba app starting 2 hours before the shift start time. Aim to do so before 90 minutes the shift starts, it helps us get an accurate count of workers on their way to shifts and we begin cancelling workers off shifts and look for guaranteed replacements around that time.
In order to confirm your shift, open the Traba app --> go to your 'Schedule' --> click on your upcoming shift --> confirm that you understand all the time, location, attire and other shift requirements --> and click "Yes. I am going". That's it, easy-peasy
Screenshots below: