you need to remove the case clamp screws and clamps...in your picture above they are at 12 and 4 and 8 o'clock. once those are removed the movement will come out...gently turn watch over and let the movement rest on your hand.
assembly is just the opposite once you have the second hand back on...except no need to depress the stem release. the stem will push into place, you may need to rotate it slightly to engage.
take extra care on pushing the hand back on. if you push directly on the end, and the tool you are using slips, you can scratch the dial (ok, ask me how I know)...you could gently place the hand back on and lay a toothpick across the attachment point and apply slight pressure until it is applied. it won't take much, and no chance of slipping.