1. Introduction

WHERE are the instructions for installing this on the MK4S with NFC???  These instructions do not cover much of what is needed

Hi there! Is it NOT compatible with the MK4(S)? It only shows MK4... Not MK4S in the title :(. Please explain and/or update if you're able!

I mentioned this below as well, but if you came here to install the quick release cable while you're still building your printer, make sure you grab four 6/32" Power Terminal Screws as shown in Chapter 6 of the MK4 Kit assembly manual at step 34: https://help.prusa3d.com/guide/6-xlcd-assembly_437030

This "add-on" should be included as standard with the enclosure IMO. 
Why:
For what it is (a cable) offers a lot of value when you need to take printer out of the enclosure for debugging/maintenance (this being exactly the moment when you don't need additional overhead).
The effort needed to install this AFTER I already ordered and assembled the MK4 kit + Enclosure is substantial (yes is my fault that I was in a hurry and didn't go through the list with add-ons).
Giving the fact that Prusa decided not to ship the Enclosure with the plastic parts for mounting the LCD externally anymore, the standard is now mounting LCD inside the enclosure.  This makes this cable the only bottleneck on manipulating the printer in/out the enclosure with ease. 
Subjective reason:
Asking this much for a cable (on top of quite the hefty price of the Enclosure) dosn't really align with Prusa values IMO. 
Thanks for your time!

Update to my previous comment, I purchased a black PSU to make sure the quick disconnect that I purchased would work.  Prusa updated the instructions above to state that the quick disconnect will not work with the silver PSU which was not there when i did my prior comment.  I do know the quick disconnect for the black PSU works fine.