After you finish with customization, you can click “Continue” from the bottom of the page.
You are now presented with a section entitled “AdSense for Content”. You can click anywhere in the text and that shows the JavaScript required to get AdSense running. This will automatically select the text in the box.
You can then copy it and paste it into your pages directly. If you use dynamic pages, you should paste this code within your template so as to ensure that it gets displayed on any page of your website. Some advertisers choose not to display Adsense on every page, and this is understandable. An example of this is a company that has adsense, may also have terms and condition which would inevitably provide legal resources which would probably be deemed inappropriate.
What is then left for you to do is get content on your page (provided you didn’t have any already). Google AdSense crawlers will soon visit your site, making sure that the ads displayed are relevant to your site’s content.