On the left hand sidebar under EVENTS, select Events. This will take you here:
Select the desired event. This will take you here:
In the horizontal bar at the top of the page, select Orders. A drop down will appear. Select +Order. This will take you here:
Select the tab that says Guests/Non Members. This will take you here:
Fill out the required fields and then select the green button titled Create Guest Account.
The guest ticket will now appear on the list of orders for the event.