There is a code on how far apart the studs need to be. Make a frame with the studs attached the size of the area you are going to build. Lift it up and nail to the floor and ceiling. Attach dry wall and plaster seams.
Build the square wall frame with 2 x 4s. Secured to the floor and ceiling with nails and shims. Use nailing to secure wallboard to frame. Wallpaper or Paint.