Obtaining shared link from VBA (API v2) - 409 Conflict

The file does exist at Desktop Work File/33602DOX.pdf.

In the code line "arg = "{"path": "/" & filename & "}", I assumed path to be the folder string, and filename to be the document string. However, upon further review of the API documentation, I see that is a misunderstanding. I worked the script a bit, but still produce the same error.

Here is the sample arg line from the API doc: {"path": "/Prime_Numbers.txt"}

Here is the line I am passing in my arg: {"path": "/Desktop Work File/33602DOX.pdf"}

I'm not seeing why my arg is not working...it appears functionally identical to the sample, but clearly is not.

Please understand - I am not a programmer or IT specialist; this is a tool I am trying to use to improve my workflow, and I do not fully understand it. Can you help me understand how I should be structuring the arg message? I realize VBA may not be your forte, but if I can come to an understanding on the proper structure that I'm supposed to be sending, I should be able to make it work in VBA. (I've reviewed the API documentation, but I don't understand a lot of that without full-blown samples to experiment with - which is where the original script I linked to comes in....)

Thank you!