Help ! where do I find the specific category or terms for taxonomies?

I purchased the plugin AZGlossary Taxonomy Index for Couponpress and I’m a little bit confused. There is a question that reads: (Insert the specific category or term. The plugin display posts inside. Insert terms id comma separated ex.: 4,84,12. Anyway you must select a source taxonomy (mandatory field)
1. I don’t know what that is or where it is located.
2. Is there a chart somewhere where I can find all of them?
3. Since this is for Stores & Categories, do I use the same source taxonomy for each individual Store/Category or do I use different ones?

Thank you.