You do not need to login to use Primo VE. When a patrons is on campus within your database IP ranges, they will be able to get to all of the content that they need without logging in. However, there are several reasons to encourage patron login:
You can use the same authentication integration profile as Alma, but depending on your authentication type, you may have to provide your campus IT with the Primo URL. The User Authentication will be populated with your Auth. Integration Profiles in Alma, plus internal to Alma (code Alma profile).
A good customization to make is to change the labels of your authentication, as some users will use your campus authentication, while others will use Alma authentication. You can do this using login labels from the User Authentication config.
Ex Libris Documentation: