Help with first hook (how & where)

[Oreamnos]

I have a query that will use the forumid in the WHERE portion of the query. I want the results to be displayed in the forumdesc table (the table that describes the forum you are currently in).

1. can i use a hook in one of vB's queries to access my non-vB content which is related to the forumid?

2. if yes, where do i start? how can i identify the exact hook_query i need to hook into? where does my query go?

thanks!
eric