Unloaded gun of course,,
Remove the forend and bbls.
Dryfire the action,,best to place a piece of wood up against the face of the breech to deaden the fall of the hammers.
Remove the triggerguard tang screws
Lift the trigger guard tang from it's stock inlet carefully so you don't tear wood up w/it and unscrew the guard from the bottom trigger plate.
Sometimes the triggers themselves interfere with the guard making a complete rotation. That's OK here, just swing it to the side 90 degrees.
-Remove the bottom rear tang screw.
-With the guard removed or swung 90 degrees,,there is a screw right in front of the guard thru the trigger plate. Take that screw out also.
The trigger plate is now free of the frame itself. It usually takes a bit of work to pull it free of the frame. Don't be tempted to lever it out w/a screwdriver. Work it free little by little. It is held at the front with a lip on the plate interlocking into the frame.
As it comes off, the top lever latch w/it's small coil spring is free to fall out. It probably will if you have the gun upside down and the trigger plate off. It's a round button shaped 5/8"d thing that you can't help but see. The coil spring just sits in the center of it. The entire piece fits into a machined circular cut in the frame.
With the plate off,,punch the sear pin out (lower rear pin in the frame) and remove the 2 sears. No spring tension on them as the sear springs came out with the trigger plate.
Lastly, on top, press the top lever over and remove the large head screw on the top tang.
It's just a short stubby wood screw but that's the last thing in your way.
With all that done, the frame will come off the wood with some carefull manipulation. Be careful of the inletting and unsupported frail edges of it while the metal is out of the wood.
When you put it all back together, make sure the safety parts are engaged properly and working before putting all the screws back in.