Chatter notifications can be accessed when creating new process or by editing an existing process. If chatter notifications are enabled for a Process, each time a step becomes active in an instance of this Process, Work-Relay looks up Assignee of this step, and creates a new User Feed record or a number of records.

Multiple records will be created if Step Assignee is a group of users (e.g., Multiple users assigned to a step, or a group Assignee such as Queue of Profile).

Feed item designates Assignee and contains basic info on the step, such as Process Name, Step Name, Record name. Feed item uses topics that can be used to filter items. Topics are:

• Process name
• Step name
• Associated Record
• Flow Instance name.

Each of them can be used to filter the list of the Feeds from the Salesforce User Interface, or to extract feeds using Work-Relay API.

In Chatter, user will receive a notification that "A flow step has been assigned to you!".  

Clicking on "View" (1) button user goes to the assigned step.

Clicking on "Finish" (2) button user proceeds the assigned step.

More information about Chatter is available directly from Salesforce