Go to the Library or purchase the ABC's of Reloading, 9th edition (Amazon, ebay, Midway USA, etc.). That will tell you the how and why things are to be done a certain way and in a certain order. Once you decide to start the reloading adventure, then some reloading manuals are a must because they will contain the range of recipies for specific powder and bullet combinations. The Lyman 49th, Hornady or Lee Second Edition manuals seem to be the most popular. I was in your position earlier this year, and did a lot of reading before I bought a single piece of reloading equipment. Urge you to do the same.
You may find some interesting vid's on the internet, but they most likely won't go into the why's. They'll mostly show you the hows.
