I've compiled here all the information you will need to find out what you're up against, which is nine tenths of the whole battle. Once you have all the parts and tools sitting in your garage the rest is elementary; it's finding out exactly what you need and how much it's going to cost that gives you such a headache, so just sit back and enjoy the videos. Afterwards you'll be prepared to wade through the plethora of various parts and tools for sale on the internet. More importantly, it will arm you with the information you need to ask specific questions so as to get exactly the information you need for your particular build. This video will show you all the parts, what they're called, and where they go in the rifle: This video will show you how the parts actually work: This next one takes you through the entire build of a basic AR15 (it's long, but it's comprehensive, to the point, and very well done): Well, now you should have a very good idea of what you're up against. Just don't forget that there are a million and one ways to skin a cat, so the information in those videos might not apply 100% to your build, depending on what parts you choose, and how many optional tools you plan on using. But that's what forums are for, so fire away with any questions that come up as your plans progress.