I am having 10 steps of activity at step 4 I am calling - queue-for-agent- calling one agent, will agent and activity run in parallel or after completion of agent activity it will come back and the actual activity will start?
and can I use the agent activity pages in actual activity?
While using Queue-For-Agent method in activity, you will have option to check-in deferred process (or) not like that. If you selected deferred means agent will process the request after commit happens in your activity, if you are not selecting deferred means at the time of Queue-For-Agent step execution itself agent will start processing it.
After step 4 got executed, 5th step will get executed. Activity will not stop execution until agent complete process.
Agent request will get processed under different Batch Requester Session, there will be no linkage between the Requester Session which is processing actual activity and Agent. So you will not be able to use the shadow page information which you are using in agent with actual activity.