Lock bolt back, remove forend and barrel, release bolt while holding handle (don't let it slam shut) and ease it forward while working out the floating chamber (tapered lookin piece out the front of the receiver).
Knock pins out and remove trigger. Remove pad, in the center of the tube holding the stock on you will see a wire clip locking the aluminum buffer plug, remove the clip and unscrew the plug, careful though it has spring pressure on it.
Remove the plug and spring-----now, there is a hole on the left side of the receiver, line the pin holding the inertia rod/bolt/bolt handle up with that hole and push the pin thru.
Look well at this as you remove it so you can put it back as is. Move the inertia rod back into the stock and remove bolt.
I use a drill, cleaning rod chucked in the drill, a 20 and 12 gauge brush, and assorted sizes of Scotchbrite wrapped around those brushes for the inside of the inertia tube, barrel, chamber, and floating chamber---with a little oil.
Do the inertia rod tube first, then polish up the rod itself. Barrel/chambers and inside the receiver. Clean the bolt and trigger group. Flush all out with brake cleaner or similar, and I go back with a light coat of Break Free CLP but any good oil will work, on all parts--inside the bolt and trigger.
The one getcha that you have left except reassembling, it is has to be timed. Oil the tube, and I-rod, put the bolt and handle back in, push the inertia rod back in (make sure the arc is up) and get those pieces lined back up and replace the pin.
Put it back together except leave the clip out that locks the plug. Screw the plug in about where it was--with the trigger in lock the bolt back.
Now, you need to screw the plug in til it bottoms out on the back of the rod, then screw back out til the bolt can be moved about 3/16" back from lock. Ease the bolt closed and locked several times rechecking this distance. Once you are certain, turn the plug back out just enough to replace the clip----lined up with locking holes.
This is a wear item, and it needs to remain about this distance, so from time to time check it to make sure it doesn't need to be reset------this is important!!
You can also remove the magazine plug and polish/clean and relube it, should be good for a long while if only occasionally shooting.
Should be ready to go. I probably missed something, doing this all by memory, ask again if something is not clear.
One other thing----check the length of the spring, I think it should be 18" long, if not, stretch it or get a new one----they aren't expensive.