Install the Balusters
Screw the balusters into the top and bottom rails.
For a more finished look, bevel the bottom of each baluster.
Check your local building code for baluster spacing; maximum separation of balusters is usually 4 to 5 inches on center.
For a composite railing system, mount the support brackets, which the top and bottom rails will rest on, using two 5/8-inch mounting screws, making sure the hardware screws through the post sleeve and into the wood post.
Some composite railing systems call for setting the balusters in the slots on the bottom rail; then inserting the balusters into the channel of the top rail and aligning the top and bottom rails. Then the balusters are nailed to the rail and the rails screwed to the brackets.