Important thing to remember when disassembling a S&W revolver is the screws location in the sideplate. A typical 3 screw sideplate has the most upper rear screw which is a flat surfaced head, the lower screw behind the trigger appears to be the same screw that is in the front of the trigger but is NOT, The front screw has been fitted to allow the crane sufficient tension when it is opened. These two lower screws need to be placed separately on your bench so as to be reinstalled in the correct location. the rear screw can also be fitted to use as the front screw but to save that fitting it is best to just separate them and reinstall as they were. Do not get heavy on the torque when reassembling the sideplate as it is evident by the screws slots being overly torqued and displacing the slot cut(looks bad).
I would also recommend the Kuhnhausen book and video also if you can locate it. The cost of these will be paid back many times by the knowledge you will gain in S&W revolvers maintenance and inspection when buying used.
Most important is to use the correct fitting Hollow Ground screw bit which can be bought separate from Brownells if you know the size overwise just buy a good set of Gunsmith Screw Drivers/Bits. This will save you a good bit of embarrassment from them buggered up screw heads.
If you need more info my email is available
Be Safe!
-Mike
Note:
I should also note since there is a "new" design that if the model smith you have is post 1987? the screw will be obviously different.