the "git add <file_name>" command leads to the error "fatal: pathspec ‘file_name’ did not match any files

Before you mark as duplicate, I am referencing this similar question: Fatal: pathspec ‘file.txt’ did not match any files, GIT

However my issue seems slightly different from the one posted there.

I am a complete beginner with Git and GitHub. I have already written a complete program and have followed the instructions to upload/commit it to my GitHub page. It appears to have worked without any issues.

Later, as further practice, I edited the file containing the source code for my program. All I am attempting to do is to upload/commit this newly edited version of my program to my GitHub page. However when I attempt to enter the command:

git add <file_name> 

I get the following message:

fatal: pathspec 'file_name' did not match any files

I thought it might be a syntax issue so I tried the “git add <file_name>” command both with and without the file extension “.txt” I also tried the add command using the “/” instead of the file extension since that’s how it appears in Git Bash when using the “git status” command. Nothing has worked.
git add error 1

Then I noticed that when I use the “dir” command the file names are represented using a different syntax. It appears that file names consisting of multiple words separated by spaces are represented with backslashes followed by a space and with no file extension, so my file: “Word Guess.txt” became “Word\ Guess” taking this into account I tried the “git add” command using this different file name representation and I wrote:

git add Word\ Guess

That gave me the following warning:

git add error 2

I don’t fully understand what the warning is saying but its obviously not the result I intended. Clearly I am missing something here. In the response given to the similar question that I referenced at the top of this post, the commenter said that the source of the problem was that the file did not exist and that you cannot add a file before creating it but in my case it seems obvious that the file exists because the program is fully functional and has already been successfully uploaded to my GitHub page. What am I not grasping?

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