[POST-INSTALL] Missing explanation at "Run the Modified GRUB Shell"

* Guide(s) in question
OpenCore Post-Install: Fix CFG Lock: Turning off CFG lock manually

* Link to page(s) with the issue
https://dortania.github.io/OpenCore-Post-Install/misc/msr-lock.html#turning-off-cfg-lock-manually

* Clearly explain the issue(s) with the page(s) (if there is a visual issue, a screenshot is required)
Here the docu suddenly says:
"Run the Modified GRUB Shell"
There is no explanation anywhere how to do that.

* Include possible fixes
I did find a walkthrough on how to do that on another page that deals with hackintosh and would have asked if linking to that very post would be an option. But the source is from a hackintosher that you do not want to work with (_starts with a "t", "on" which there sits a "y"..._).
Copy & pasting would be unfair to the original poster. So what can be done here? How can this "leak" of documentation be filled?

Start at the OpenCore Post-Install page section “Turning off CFG lock manually,” especially the instruction “Run the Modified GRUB Shell.” Review the surrounding steps and add an original explanation of how that shell is obtained and run; the issue is done when a reader can follow this step without relying on an undocumented external walkthrough.

Written by the indexing model from the issue text.