You need to purchase some Rail bolts, they are wood thread on one end and machine on the other.
Set your rail in place and mark the bottom on the lower newel and the top on the upper. In the center of the newel post 1/2" up from the mark drill a 1/4" hole and insert the rail bolt until only the machine threads show. On the bottom of the rail drill a 1" hole centered 1 1/2" back from the edge. Now drill a 3/8" hole in the center of the rail on the edge that hits the newel post 1/2" up from the bottom. Insert the star nut and washer and tighten with a nail set.
To do the upper attachment, drill a 1" hole in the center of the rail 1 1/2" back from the edge on the top. Use 2-4"wood screws to attach. Plug the holes with 1" oak plugs.
Hope I didn't leave something out, I could have it installed in the time it took to type this out.