It's not necessary for you to create an EPC chart from scratch. Using built-in and customizable templates will save you tons of time. Have a quick start with this editable online sales EPC template.
From this EPC flowchart templates sharing community, you can either upload your wonderful design works or download existing EPC diagram templates for reference. As vector files, all templates are available to edit and customize. Explore whatever fits you best and download for your own use.