Open the U-M Dropbox website. A quick link is available via the Applications tab under Other for your convenience:
Sign in with your uniqname and UMICH password, and click on the Upload button on the Dropbox Home page:
Browse to /afshome/uniqname to see your AFS files (click the < arrow and then the hard drive icon to see it):
Finally, select the files you wish to archive in Dropbox.