It doesn't need to be taken apart for normal cleaning and maintenance. If you really feel the need to take it apart, get this book:
"The S&W Revolver: A Shop Manual" Book by Jerry Kuhnhausen
Model 19
You can request an owner's manual for free at the S&W web site.
Go to the S&W website. You can request a manual for free or download one.
first you c*ck the gun back and lift up the back, then pull forward all in one motion.The rest is screws
100-5000 USD depending on EXACTLY what you have.