Remove the barrel, then slide a finger up into the bottom of the receiver through the bottom magazine loading port and push out on the right, then left or left, then right slider retainer flat spring(s), one on either side, while gently pulling forward on the forend slide. The dual slide bars are released and the whole works simply slides forward on the magazine tube. Put it back the same way; really, it couldn't be easier. If you wish to remove the trigger/hammer assembly, first, punch out the two pins and it pulls straight down and out. You gain a little more working room and can see what your doing, but it's not necessary. The gun should be right side up.
It takes longer to say, than do......hope this helps .....mike