Understanding conditions

Is there a good site or place to understand what the conditions are used for?

... these forums?

What is your specific question?

I have a specific question about conditions.

If I have selected conditions:
extension is gpx
kind is document

Why does Hazel copy .idx and.kmz?

Likely you have changed the type of search hazel is doing by modifying the dropdown just above the condition pane.

For those conditions to be AND'd together, make sure it reads:

if (all) of the following conditions are met for (the file or folder being processed):

currently is running on downloads folder and reads :

if (all) of the following conditions are met for (any of its subfiles or folders):
extension is gpx
kind is document

so why does it pull .idx and .kmz?

Read my previous post. You're not matching files, you're matching folder content.

ok - I got a running rule

I see the point about the folder content. I just do not understand why it would do all the gpx (good) and then throw in kmz and idx (puzzling).
I'll keep practicing.

Note that Documents matches pretty much anything that isn't a folder. I'm guessing you still have it set to "any" instead of "all".