I would suggest that you not take apart the choke assembly unless you absolutely have to. Unscrew the screw that attaches the lever to the choke valve and the actuator rod. This will allow you to lift the top off vertically without having to disengage the rod. Make sure that you get the right top gasket. The kit usually comes with several and you need to match it exactly with the one you took off.
Your carb probably doesn't have an APT but I found a great way to set it for those who have one. I mark the depth of the top of the jet on the rod just above the top step with a permanent marker. Drop the APT in without the spring and adjust until the top of the mark aligns with the top of the jet. This will get you very close to having the shoulder of the rod in the correct position in the jet.
I have taken mine apart about 20 times now including several others I had laying around. It really is pretty easy once you do it once or twice and you know the tricks.