1. Click the 'Donate Now' button on the ad. This will take you to the NPO's Google Checkout page.
2. Sign into your Google account. You need a Google account to donate this way. If you don't have one, click the 'Create an account now' link and follow the instructions to set one up.
3. Direct where you want your donation money to go. Note that not all NPOs have a Google Adsense account through which you can donate.
4. Enter your payment information in the following window, then click 'Next' to confirm the purchase.
5. Click 'Submit' to make your donation.