In Zimbra, a shared inbox would show up in your folder list. In Google, things work a little differently.
First, the Technology Help Desk will need to share the inbox with you. We've already done that for the accounts that were on Zimbra.
Second, you need to ACCEPT that share. You would have received an email from "Humboldt State University Team" with a subject of "XXX has granted you access to their Humboldt State University account -- accept or deny?". Go find that email and click the link to accept the request.
Finally, about 30 minutes after you click that link, you'll notice a little drop-down arrow next to your email address at the top of the screen. Click on that arrow and click the name of the shared inbox. The shared inbox will open in a new browser tab  or window. You'll have full access to the mail in this account (including sending).
Outlook users will need to open that shared account. See Opening a shared inbox in Outlook .
If you need this account shared with someone else, you'll need to contact the Technology Help Desk  or call (707) 826-HELP (4357).