For building though, building a 1911 isn't like putting together an AR and it's cheaper to buy one if you don't know what you're doing, possibly even if you do.  All of your parts have to be compatible, i.e. Government vs Commander, Series 70 vs Series 80, etc.  I myself have a good working knowledge of the platform and I've bubba'd a frame by not going slow enough for my limited ability.  There is a considerable amount of hand fitting that goes into it.  Your slide has to be cut to accept your particular sights, your frame has to be cut to accept your grip safety and some cutting may need to be done to fit other parts.  You also have to fit and tune your extractor, safety/function test it and get a finish applied.  In addition to all of this you'd need specialized tools for fitting the frame and slide.  The nice thing about the C&S trigger kit is that the hammer and sear are pre-fit.

In addition to those parts listed above, which should have all of your pins and springs in them, for a basic setup you also need a Main Spring Housing, grip safety, thumb safety, guide rod, guide rod plug, extractor, and extractor pin is probably not in that kit, a firing pin, grips, grip screws, grip screw bushings, mag release, a mag release lock, a trigger, a plunger spring, frame and slide, sights, magazines, and a barrel with bushing, link, and link pin, and a hammer strut. Your slide has to have an ejector and a plunger tube installed as well. I'm at work, so I'm probably missing some small part in there somewhere since that was all from memory.  If you're going to attempt a build, step one is looking at a diagram, familiarizing yourself with all of the parts and making sure you have all of them that you'll need.

If you have an iPhone, iPod Touch or Android look up an app called Gun Disassembly 2, they have an interactive 1911 that lets you do a complete 3D take down with the names of the parts, as well as an x-ray and slo-mo view of function.