713 Music Hall – General Admission Standing Room

Hi, I'm purchasing tickets to this venue which i haven't been before. I'm trying to get floor tickets so that I'm at the very front of the stage, but i see that when I'm about to purchase it gives me a seating of GA1. So when I go to the concert, will they assign me a spot to stand or is it first come first serve if you want front stage? Sorry if its a dumb question 🙂