There are now two ways to submit a sub request: 

Go to your My Schedule page click on the shift for which you need a sub, type in a reason for the request (this is optional, but this could help convince your supervisor to approve the sub request), verify it is the correct shift, then click request sub! 

You can also go to the main Schedule.  Make sure you are looking at the Employee view (picture below), and scroll down to your name.  

Click on the shift for which you need a sub, type in a reason for the request (this is optional, but this could help convince your supervisor to approve the sub request), verify it is the correct shift, then click request sub! 

Once a sub is requested, you will see the color of the shift change to orange, and a text or email message will be sent out to alert the other staff at your location that you have requested a sub.  You will also see it in the Open Sub request queue so someone else can take it.  

Remember that you are responsible for the shift until your supervisor approves the sub.  Once it has been approved and you are no longer responsible for the shift, it will disappear from your schedule!