My cousin has one of those (whith a cracked bolt, for which I've been looking for a replacement for awhile), first do like your 870 ... uncrew the cap, take out the cap, slide the handguard off then wiggle the barrel around and it (should) come out ....
Then comes the tricky part .... First find the trigger assembly pins then knock them out, and pull out the trigger mechanism like any 870 .... Then look underneath it and you'll see a hole at the bottom of the bolt .... Find something to fit in said hole ans shove it in, hold it back, and you should be able to pull the operating handle right out. Pull out tool and the bolt should come out .... That's the way I figured it out after well after 2 hours of fiddling around.