He points to the buttons (lower left of the screen) that trigger the CS record, stop and play functions when he uses them.

So it's pretty easy to hear how he starts with the arranger just running the Em chord, then he hits CS record and plays the Em///Bm pattern and hits CS stop (although he could also have hit CS Play and the loop would have automatically continued), the Em plays until he hits CS Play, then the two chord loop starts. He then uses the loop to play up until the bridge, when he hits stop, plays the bridge live, then hits play on the CS again.

Personally, I might have recorded a longer loop including the bridge and the last 'verse' section, then looped that for a hands free full 2nd verse, then overwrite that with the simple 2 chord loop for the extended solo section, but that's the beauty of the CS... plenty of ways to skin a cat!

But the real trick about the whole feature is, at no time, with all the CS start, stop and Play, does the arranger ever stop. It's all seamless, where you are chording, where the CS is chording, whatever. You can perform fills, breaks, variation changes, even entire style changes (although I think with a 5/4 loop, you will need to change to other 5/4 styles otherwise things could get weird!) while the 'Third Hand' keeps playing those changes for you.

This simple one bar chord loop is the most simplistic use of the feature possible. You can use it for much, much more (up to entire verse and chorus structures, for instance), you can use it for extended vamps and solos, whatever you need.

If you think about it, a vast amount of songs are basically a simple 'head'. so if you tend to play a structure like Intro-Head (1st verse)(2nd Verse) solo1, solo2, Head(last verse) and outro, all you need do is record the first head you play, then hit CS Play, and that's the last chording you need do until the outro!

For more complex pieces, record the verse and chorus, play the bridge yourself, the hit CS Play again, and that may be most of the song. Especially as the first verse (for us singer types) is generally just us chording with minimal RH input, this makes it easy to CS Record the changes, then they are ready to go for when we want to get down and solo...

The only caveat with the Korg CS is, I highly recommend a Korg EC-5 multi-footswitch to do the job, as for some ungodly reason, Korg made the front panel controls a multi-button press for each function, trickier to do right that a single button press (plus anything that allows you to trigger important, time critical things AND keep playing is a good thing in my book!).