Pretty easy, actually.
If you haven't already, remove the crane/cylinder assembly from the gun. Get a minimum of 3 fired cases, and insert them into the chambers. Clamp the ejector rod in such a manner that it will not be damaged (brass or plastic vise jaws are ideal for this, though padding a standard vise with a piece of leather works as well.)
Once firmly clamped, simply turn the cylinder counter-clockwise (the normal direction to unscrew something), and the ejector rod will be free from the cylinder. You can pull out the ejector rod, and remove the cylinder from the crane.
Coming out the front of the cylinder is the ejector spring, which should have a little collar on the end. (If it doesn't, check the ejector rod to see if it's stuck there; look inside the cylinder tube on the crane; if not in any of those places, start looking on the floor for it!) You can pull the spring directly out; it is a light press fit onto the ejector star stem. Finally, pull the ejector star from the back of the cylinder. You should be left with just the cylinder, crane, ejector rod, collar, spring, and ejector star - it's a very simple mechanism.
Assembly, of course, in the reverse order.
Hope this helps!