To install wooden balusters, prepare the stairs by drilling holes in the stairs for the baluster pegs. You can glue or bolt the balusters to the stairs. Attach the handrail with glue and nails. Install iron baluster in the handrail, and drop it into holes on the stairs.
If there are no existing baluster holes in the stair treads, use a stair drill bit to drill the necessary holes. The special bit creates a thread for a baluster bolt. Drill a hole in the bottom of the baluster, insert the bolt, and screw the baluster to the tread. If bolting is not required, use construction glue to secure the baluster.
Once all the balusters are installed, secure the handrail using nails and glue. Conceal any nail holes with putty and paint.
When installing iron balusters, drill holes into the tread if necessary, and cut the balusters to length. Remember to add 1 1/2 inches to the desired length to account for holes in the tread and handrail.
Push the baluster into the handrail, and drop it into the tread. Make notes of any necessary adjustments. Use epoxy to secure the balusters in place. Measure twice and cut once, regardless of the balusters' material, so you can properly install everything the first time.