And what is the sequence of loading these rules? (harness > container > assignment properties(route activity) > flow action pre activity ) Is this correct ?

Thanks.

Build_For_Change, you are talking two categories. It creates a new assign page (assignment). Takes all your configurations on your assignment, routes it in the background.Saves the assign reccord in the database table. After this is performed, depending upon your configurations it loads the html from the harness you configured on the assignment. Please run tracer by enabling all rulesets, stream rules and activity rules. You would understand clearly. Hope this helps.

Thank you very much. Yes I got high level undestanding... This helps me lot to go further....

In Pega 7.1.8, how can we do the auto submit of flowaction as soon as it loads. I wish to submit the flowaction once i select it from the take action (other action in pega 7.1.8) and move to next assignment directly. 

allow auto process on assignment shape works?

could you please comment on why do we need to have an assignment which needs to be auto submitted when not required?

also please try ResumeFlow as preActivity of the flow action

refer GoBack assignment.

I hav tried both ResumeFlow, AdvanceFlow, FinishAssignment and even GoBack.  All these does not help. GoHelp stops on the same assignment. It does submit the flowaction. Other three method looses the hold on the WO and produce error. Finally i found the solution here in this pdn article. There was a change in the HTML. refering this below code from the pdn article, solved my purpose.

https://pdn.pega.com/support-articles/actionautosubmit-does-not-submit-the-flowaction

My requirement was, i have two assignment, one in th parent flow whereas second in the subflow. In the second Assignment, there are three Connector. On selection of one of the take action (connector), user is navigated back to assignement 1 in parent flow without any action needed to perform on the current assignment. So i wanted to auto submit the flow action as soon as i select it.