>> "I put the API key in the code"
That's the error. Don't put the API key in your app. It tells you that on the Settings page.
More specifically, what you should be using is here: https://wyday.com/limelm/help/using-turbofloat-with-vb-dot-net/
The Version GUID is described multiple times in that article starting with the first paragraph and a picture showing it. Let us know if you have any other questions.