Yes, here is the procedure
1) Go under Options -> Settings
2) Set your Download Age to 2
3) Make sure your Storage Age is > 2, set it to the number of days worth of headers you want to keep on your hard drvie
4) Go to the Groups List tab
5) If you've already subscribed to a group of interest, it'll be listed here. If not, go under Options -> Add Groups and select a group or groups of interest. By default they get added to the "Unsorted" folder in the Groups List tab
6) Right-click the group of interest and select "Download Latest Headers". If you have previously started downloading headers from this group, it would have used whatever the Download Age was set to which is 30 by default I believe. To tell Newsbin to start over using a new Display Age setting, you'll want to right-click the group, select Post Storage then "Use Download Age" before doing your header download.
7) Monitor the Download List to watch the header download progress then the Cache display at the bottom of the Newsbin window to make sure the headers get processed into the database. When Newsbin is idle, it should look something like "Cache 200/200 (0)". If there are numbers in the parenthesis, that represents a backlog of headers to be processed. You won't be able to view all the headers until that number goes to 0.
8) After header download completes, right-click the group and select "Show Posts". This command honors the "Display Age" setting in Options -> Settings. As long as it is > 2 in this case, you'll see your posts.
The next time you do a "Download Latest" on the group, it'll pick up where it left off and download any headers that have appeared since the last time you checked.