How to Put an Ad on Tumblr

1. Log in to your Google AdSense account at Google.com/AdSense. You will need to have your account approved to begin making money through advertising.
2. Click the 'New Ad Unit' button. This displays many choices for your new ad. You should create a new ad unit for each section you wish to place ads on within your Tumblr theme.

3. Complete the form as required. Choose a name for your ad unit and select the ad size you wish to display on your Tumblr.
4. Click the 'Save and get code' to access the raw JavaScript for your ad unit. You will need to copy this code by selecting all the text with your mouse, then typing 'Ctrl' and 'C' to save the text to your clipboard.
5. Log in to your Tumblr dashboard and select the blog in which you want to display Google AdSense ads on.
6. Click the 'Customize' link to bring up a list of Tumblr theme options. This will allow you to edit preferences, such as colors and descriptions, along with editing your theme's raw HTML.
7. Click the 'Theme' link in the header, then click the 'Enable custom HTML' button. You should then see the raw HTML text for your Tumblr theme.
8. Paste your Google AdSense code anywhere within your theme's HTML by clicking to put your cursor in the desired location, then typing 'Ctrl' and 'V' to paste the JavaScript. Test your placement by using frequent previews to find the ad location with the most impact.