Acquisition Plan Summary approval process and milestone update

Hi,

How is the approval process for acquisition plan summary configured?  I've been trying to submit an acquisition plan summary for approval in a vision instance.  It always turned out to be pending for approval.  In my course of troubleshooting, I thought of decreasing the amount.  And that made the document to have an Approved status.  But I don't know how the system determines the amount and who approves acquisition plan summary.  Will appreciate your responses.

In the acquisition plan summary, we can set milestones and specify due dates and notifications.  But how do we update the milestones in the acquisition plan summary document?  How do we put in the actual completion of the milestones?