What would you add to this wedding decor?

I think if it being used for ceremony space, I would add drapery along the walls, chairs would be covered with chair covers and ribbons tied on the back area, aisle runner in the middle to separate the rows of chairs and flower Center pieces with candles. For the reception, drapery would be added, could use up lighting to accent the room, add lateens for the top of the celiing, add carpet to the ground and in the middle add the dance floor, head table would be along the wall with the cake, lighting for the dance floor would be like snow glowr effect and centerpieces would be simple with candles and flowers depending on the theme.

I would get draping all around the room along with uplighting! Because its a high school I feel like a disco ball light in the middle of the dance floor would be fitting haha! Also I would have a snack table with all sorts of different appaetizers! Round tables for sure as I am not a fan of long tables. As for the "head table", I think a sweetheart table would be perfect because there is always the prom queen and king and so I think that would be fitting as well!! Maybe a starry night theme since I know high school dances usually had some sort of theme!

I would do a balloon arch! Haha I used to make them in high school and college so I feel like it would be fitting.

Balloon arch

I would probably want to do pipe and drap along the walls with uplighting to make it feel more like a wedding space. If you could do draping on the ceiling as well to make it look less like a gym that would be cool! Maybe create a lounge area with couches?

I would probably do rounds for dinner rather than long tables because I think it works better for mingling and talking at the table. Because you have so much space, it would be great to set up different serving stations with different types of food like sushi or a pasta station or a carving station.