If you are interested in learning to improve the double action trigger, then I highly recommend Jerry Miculek's "Trigger Job" video. This video gives a good introduction to the function of Smith & Wesson revolver actions and how to work on them. In the video, you may notice that Jerry does not use any power tools, and I think that using only hand tools is good guidance for any beginner.

I have looked at some of the youtube videos on smoothing up S&W revolvers, and I have not found any videos that I could recommend. Of course, I have not watched every video, but some of the ones I have seen contained critical errors. So I do not recommend youtube as a source for this information.

I will also offer a differing opinion about dry firing revolvers to smooth them up, I am not a fan of this method. The double action trigger will smooth up noticeably with use, but this method is not comparable to a quality trigger job. If hardened steel parts have significant rough spots or burrs, those take an indefinite time to smooth out through wear. A gunsmith will find those spots and stone them to be flat, true and smooth in just a few minutes. If you want a good trigger, I recommend letting a qualified gunsmith do it or start putting in the real study on how to do it yourself.