Here's the YouTube link for the video.I like this one! You have a foreground that "pops" and it leads you in to something that seems to go on forever!
Nik Silver Efex is my favourite tool for selective colour, with other programs it is harder to control what area you want to be in colour.
The control-point in Nik makes it easy.
I would guess that you used 3 control points at least for this, one for each colour/shade.
One thing that I have learned is that the colours can bleed into other areas and in that case a control-point with SC turned down in that area takes away the bleed.
Do you have a link to the video? (I'm still learning.)