Other then the Error I get sometimes when I use it, what does the Prospector even do? like how does it work? Cause so far I don't see anything happening.

It highlights resource locations in a radius of 32 tiles.

Will it highlight the resources outside of unmined areas or only within the areas you have mined?

also does it have to be used above or below ground?

Use it underground. It highlights also in uncovered areas

okay, then I would suggest a config for scanning distance so people can customize that if possible.

or the addition of a long range variant