The Tools category contains three options - “Ad Groups”, "APIs" and “Pixels/Postbacks” - which allow you to manage various aspects of the offers you are promoting.
Ad Groups - Here you are able to manage multiple creatives and offers. As with the functions mentioned above, you have the ability to filter your data displayed. You can filter by keyword, date/time and activity status. You also have the ability to change the activity status of any creative/offer.
Pixels/Postbacks - Here you are able to manage third-party conversion tracking pixels and postback URLs. From this page, you can either delete or modify the tracking pixel code/postback URL. If you need to further modify either the pixel tracking link or postback URL, simply click on said item and you will be redirected to it's detail page where you can do so. Here's the comprehensive guide: Using Pixels/Postbacks
APIs - This page shows you how to grab your Affiliate API key and the info that you need to get started with it.