To set the sales channels that your Event will be available for purchase on, you will need to do that on the Event Schedule level.
In the ACME Back Office, navigate to Events > Templates and select Edit next to the desired template.
Once the template is open, select the Schedules & Resourcing tab and select Edit next to the schedule that is currently live.
Once you are in the Schedule, select the Pricing tab. You will see the available sales channels on your Price List. Either select or de-select the sales channels you wish to have your tickets available for purchase on and select Save & Close. When you are ready to publish and make the tickets available for purchase to your visitors. select the blue "Publish" button. Tickets are now available for purchase on the sales channels you selected.
See Defining ACME Sales Channels for more details.