Google Drive is available to all users that have a Google login. Google Drive lets you create documents (text document, spreadsheet, slideshow) and store them online accessible with your Google credentials. Documents created in Google Drive are able to be shared and edited with people you grant access. You can also upload documents to Google Drive and access them from location you have a connection to the Internet.
If you are a Gustavus user, you have a Gustavus Google Drive account. If you are also a Gmail user, you would have a secondary Google Drive account. These two accounts are separate, however you are able to share the documents between the accounts.