As an employee, when you receive a canuwork invite from your employer, you will need to create a canuwork account, download and login to the app, and accept the new invite.

Once you have the canuwork app and have logged in, you will need to go to the Profile screen.

You will see that there is one (1) item in the Pending area.  Tap on Pending to view invites.

The Pending invite will be displayed and you must Accept or Decline the invite.  Tap accept to join the employer's canuwork roster.  This will allow them to view your availability and send you work requests when they have a vacant shift.  

You will notice that the employer is now listed under Joined in your Profile screen.  
Please ensure you have marked your availability in the Calendar screen of the canuwork app to ensure your best chance of securing work.