@gsandy in the future please post things directly to the forum thread. The volunteer helpers should not be forced to download a PDF just to get an explanation of what you did. And some can't or won't do that so you are harming your chances of getting effective assistance by doing that.
I'm forced to make a significant effort to transcribe the content from that PDF to my forum post just so that I can effectively respond. I shouldn't have to do that. Help us to help you!!!
It is a bad idea to name your sketchbook folder "Arduino Libraries" The sketchbook is a place where two things are stored:
When you name it "Arduino Libraries", you are indicating that it is only a folder where libraries are installed, which is misleading.
First of all, it clearly shows that it is under a path that contains Arduino\Libraries. That is not the same as the path you have in your "Sketchbook location" preference:
c:\Users\Grant\Documents\Arduino Libraries
Do you see that in the preference you have a folder named "Arduino Libraries" (note this is a single folder with a space in the name, giving this structure:
c:/
└── Users/
└── Grant/
└── Documents/
└── Arduino Libraries/
│
...
whereas the folder structure shown in your Windows File Explorer screenshot is a subfolder named Libraries under a folder named Arduino, giving a structure like this:
<unknown>/
└── Arduino/
└── Libraries/
└── grbl/
├── grbl.h
...
They are not the same!!!
Another thing that is not the same, is you named the folder Libraries, while the instructions clearly state that the folder name is libraries. Note the case of the first letter is l, not L. You can sometimes get away with this type of sloppiness when using Windows because it usually treats paths in a case insensitive manner, but it is really a bad idea.
You must pay close attention to details and be very precise if you are to have any success in Arduino and CNC endeavors.
Note that your Windows File Explorer screenshot does not give us all the information we need because it only shows a fragment of the full path under which you installed the grbl library. You might know the full path, but the only information we have to work with is what you give us here on the forum so we have no way of knowing what the parent path is above the Arduino folder we see in the screenshot.
So go back and set your "Sketchbook location" Arduino IDE preference to an appropriately named folder, then start from the beginning of the instructions once again. This time read them extremely carefully and follow them exactly.
As before, if there is anything in the instructions that is unclear to you, you are welcome to come back here and ask specific questions about the instructions. We are happy to help with that, but otherwise we can only tell you to follow the instructions. If you follow them correctly then you will achieve a successful installation of the library and be able to open and compile the Grbl sketch in Arduino IDE.
