How familiar should I be with the original show?

My best friend and I don’t know anything about Phantom but we directed one of the phantoms in a show many moons ago so we are going to see him :) He told me you don’t need to be super familiar with it although it might help to know the plot. Curious to get thoughts from big fans, should we listen to the score/read the plot/etc or are we good to go in blind? (We are very into Broadway just not really ALW people)