Riverside seating question

I’m sure it’s been asked and answered a million times but can someone explain the different GA sections and how they are separated. I get the floor is GA Pit then GA First Floor behind that but how is the balcony GA set up, are there boxes/seats in front of of the 2nd floor GA balcony? Or could a 2nd floor GA Balcony ticket get you on the “rail” of the balcony if you get there early enough?