To build a process flow using EPX, you should:
Make sure you have already defined EPX users and created the components you need for the process flow, including roles and work item types.
Create the work item viewers that will be used in the flow. Viewers can be generated automatically based on a work item viewer template, or they can be created manually.
Add activities to the process flow canvas and set their properties. Right-click an activity and then click Show Errors in the shortcut menu to display any errors.
Add transitions between the activities.
If you want to include a subflow, you can add any subflows, personal subflows, or remote subflows that have already been created.
Validate your flow by clicking the Validate button in the toolbar and fix any errors that are reported.