For several years, I taught myself (very slowly) how to begin engraving...I bought several books, but none seemed to be very helpful for me also starting out at "square zero". The videos put out by GRS and the ones Brownell sells of Linton McKinsey instructing were much better for me as I could see what the engraver was doing rather than just reading about it. Actually, now, there are several web sites and youtube videos that are a wealth of free information about engraving. Here are two that I really like:
http://www.igraver.com/
http://www.masterengraver.com/
The recently published book by John Shippers is also excellent in a very important area. The mechanics of engraving are, obviously, important to learn, but much more difficult, at least for me, is designing
what to engrave. Learning the engraving design features that are appropriate to longrifles, modern guns, etc. was and remains a much greater challenge for me. John's book has been a huge help in that regard.
However, I must say that when I took some hands on lessons in person with a wonderful engraver a few years ago, I learned more in a week than I had managed to teach myself in 5 years. GRS offers a myriad of classes. I have not taken any of these but I do use GRS tools and have been very happy with the tools and the service. Here is a link to their course schedule. You might also just poke around their web site and the site for Lindsay engraving tools:
http://www.grstrainingcenter.com/schedule/
http://lindsayengraving.com/
As far as tools go, the minimum you will need is two or three styles of graver, a chasing hammer, sharpening gear, and some sort of work holding device. You can start simple and get more complicated as you go or you can jump in and buy some of the more sophisticated gear right off the bat, which is what I did. I knew I wanted to learn how to do this, so I didn't want to creep up on it slowly any longer. (I'm getting too old to do things too slowly...I am running out of time...) John Shippers book has an excellent section on tools and gear you may want or will need. I think his book would be an excellent place to start, so buy it first.
Hope this helps.
DaveC2