Hello, I wanted to make a recording studio in the basement 
dimensions of 2.5 meters (maybe 3) by 1 meter, the point is for 1 person to enter. I already have a table and a chair, but I have to soundproof this room. I thought it was best with polystyrene, but they advised me to do it with egg cartons, but I do not know how to attach them to the wall so that they would not get there, and it is not about drilling the walls because it does not make sense.
PS: If someone had another way to soundproof (also cheap) I would be very grateful because it is important to me
more or less it looked like this

dimensions of 2.5 meters (maybe 3) by 1 meter, the point is for 1 person to enter. I already have a table and a chair, but I have to soundproof this room. I thought it was best with polystyrene, but they advised me to do it with egg cartons, but I do not know how to attach them to the wall so that they would not get there, and it is not about drilling the walls because it does not make sense.
PS: If someone had another way to soundproof (also cheap) I would be very grateful because it is important to me
more or less it looked like this
