Since some people don’t have access to this tool directly from your AdWords account, you can access it by using the following URL:
https://adwords.google.com/o/Targeti...T&__c=CAMPAIGN
But, you must replace the ACCOUNT & CAMPAIGN with the actual numbers for your URL in AdWords.
To get this just login to adwords and click any of your capaigns. Then you will see the URL will have u=(some number) and c=(somenumber). u being your account number and c being your campaing number.
Paste those numbers into the above and you will have access to the tool.