I hope you'll to take a look at the resources below from the AdWords Help Center, and the AdWords Learning Center - which will give you what you need to know to proceed.
From the AdWords Help Center:
How can I target my ad campaign by language and location?
[adwords.google.com...]
From the AdWords Learning Center (HTML version)
Lesson 2a: Targeting by Language and Location
[google.com...]
Please note that there is a multimedia version of this lesson (2a) as well, available from this page:
[google.com...]
AWA