Here's a link to cybrguys' album showing a H&R 925.
http://www.thefirearmsforum.com/album.php?albumid=680
Your 925 was made in either 1971 or 1972 (I don't have an H&R serial number chart handy right now so I'm not positive.
It's the same basic frame as the 999 Sportsman .22lr revolver except chambered for .38S&W.
For basic cleaning, no further disassembly is required.
If you need to go beyond that, I would recommend one of the good aerosol cleaners or even a trip through an ultrasonic cleaner.
That particular series, like most of the other H&Rs, can be kinda tricky to reassemble if you're not familiar with the action since everything is loaded into the frame from either the top or bottom and the parts are pinned in place. Stated in the manual, they just weren't built for simple teardown by the owners as basic cleaning can be done with just the action broke open.
You can look at a schematic for it over at Numrich Arms for a little more detail...I'm not good at describing how to tear down the action in a web post or two.
http://www.gunpartscorp.com/Manufacturers/HarringtonRichardson-33274/Revolvers-36449/925-38108.htm
And welcome to TFF. Maybe someone else here can give you a better description of the procedure too.