Open the workspace related to the past meeting that you are looking for and click on the "Past Meetings" tab. You will then be able to see all the past meetings that you have had and the most recent past meeting will be shown at the top.
Note: The name of a past meeting can be changed by clicking on it and confirming the rename but not the content in a past meeting (context is read-only)
When a past meeting is opened, it will show all the closed and open agenda items. And if you go ahead and open an agenda item, it will show the information it had at the time of finishing the meeting.