When you are hanging a light fixture in the ceiling, you have to fasten it properly or you could have a catastrophe on your hands. Nailing or screwing an electric box to a rafter provides sufficient support for fixtures which weigh 40 pounds or less, but chandeliers often weigh more than that. Most fixtures have all essential for hanging them, but if you inherited a vintage chandelier without these accessories, you will need to purchase them. Typically, a hanger bar which attaches to adjacent joists provides all of the extra support you want.
Climb to a stepladder and, using a nail, punch a hole through the ground drywall at the place in which you want the chandelier to hang.
Go in the attic a locate the hole. Center a chandelier brace, which can be an electric box attached to an expandable support pole, over the hole so that the rod extends in the direction of the joists on each side of the hole. Trace the outline of the front part of the box using a pencil.
Cut around the outline using a drywall saw to make a hole for the box. Insert the box in the hole while you unscrew the worm push the pole to lengthen it and compress the mounts on each end against the joists. Arrange the pole so that the seams of the brackets are touching the ceiling drywall. When they are, the leading edge of this box will be flush with the ceiling.
Screw the brackets to the joists using 1 1/2-inch wood screws. The screws could be supplied with the electric box.
Climb the ladder and screw the crossbar, or adapter, which came with the chandelier into the electric box using 3/16-inch machine screws. If no crossbar was supplied, use a universal crossbar.
Wire the chandelier to the primary circuit, attach it into the crossbar using the screws supplied with it. If you don’t have some screws, you might have to improvise because versions vary, and no sort of screw functions for all of these. Ask your neighborhood hardware dealer for aid.