This is the 3rd railing I've had to install on a house. It is not a difficult job, but can be if not approached carefully.
The most difficult railings I've installed were the metal posts that need to be bolted into cement, it is quite difficult to drill into cement and mount the bolts, i've also found that it usually requires some epoxy to keep the bolts in properly.
The most recent railing I installed was a lot easier, I was able to install a 4x4 post and the other end of the railing bolted to the house.
Dig a hole 30 inches, install 4x4 post, mix up one bag of quickrete, set post level and let set for at least 24 hours.
Cover 4x4 post with decorative sleeve.
Cut railing to length.