Most of your customers will do a bit of research online before they finally settle on a product they'd like to purchase or choose a service to commit to. In fact, many of your visitors will likely see your ad multiple times and may even click on it more than once before finally converting, and they'll probably use slightly different keywords to research during this process. Search Funnels in AdWords, including assist click and impression reports help you analyze this search path that leads up to a conversion.
You will need to have conversion tracking enabled in your account, and your campaigns will need to have generated some conversions.
To analyze which keywords help guide your customers toward a conversion, perform the following steps: