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 Ticket. A drop down will appear. Select Ticket Design. This will take you here:

Within the Ticket Designer box, fill out the corresponding fields:
- Ticket Header
- Ticket Code Text
- Event Details
- Additional Content
- Custom Styling
Then, select the green button located at the bottom of the screen titled Update.