if you had on your 9820 : - BBID configured - and BBM6 or BBM7
then on your 9320, if you log in BBID and instlal BBM7 you will get your BBM contacts back.
If you have made a backup of your 9820 on your PC thanks to the free "Desktop Software", and if you have BBM6 on your new 9320, you can restore the BBM database using the Desktop Software.
if you were in several BBM groups, you can ask someone to invite you to those groups. You will then be able to readd the members of those groups, as BBM contacts.
other from those assumptions, I see no other solution.
That being said - install the Desktop Software and do frequent backups of your device - install BlackBerry Protect and configure it - log in BBID, and install BBM7 so that your BBM contacts are stored on RIM servers.
The search box on top-right of this page is your true friend, and the public Knowledge Base too: