If you come off anonymous I’d be happy to explain this to you and help you out with more information.
But to get a photo pass you either need to be on assignment through a publication, or be tight with the band. There are some bands I’ve worked with a bunch who I can reach out to when they’re in the area or they will hit me up and ask if I’m coming through and will take care of my pass and ticket. If you’re not doing it that way and you’re on assignment, either you or your editor has to coordinate the photo pass through the band’s publicist.
Also, to be completely honest with you: the more you teach yourself on the own, the better. You are going to have to Google a hell of a lot to find artist’s contacts, and you could have probably found more info on this on Google like I did to figure out how to request for my first shows.