Brilliant! - Great work. More power to your elbow Mattie.
Might I make 2 suggestions? And yes you did head this up as a Basic tutorial.
#1 - What I would add too is the "option" to use the eye-dropper/colour-matcher. With this you can "drag" over the "green" to obtain a range of greens. This has the effect of making your initial , well, range of greens more tailored to the actual green and this could make the handle of the the Skull disappear more than at present. Also, having a more accurate green range, the high and low levels adjustments will be even more effective.
#2 - The other thing to remember, it HAS caught me out in the past, is to ensure that the keyframe SYNC lock disengaged. Otherwise the chroma "could" vary over the duration of the event.
And yes, you did say basic, so please take my comments as more of a "nudge" than a crit - yeah?