Update: We've made changes to our pricing and plans. Please review the updated details on our homepage. Thanks for being with us!
After that, you can check a creative on your website or check it on a new window.
Please note that creative may not appear in the "Preview" tab itself due to Google Ad Manager's technical limitations. Try to check creative on a new window or a site.
More about how to add creatives, you can read on Google Ad Manager's official pages.