Go to Blogger.com, log in to your account and click the "Design" link next to the site you want to edit. Click the "Add a Gadget" link in one of the available layout sections. A pop-up window appears.

Gadgets are one way you can customize your Blogger page. A gadget adds a a customizable element to your blog. Many gadgets are available on the Blogger service, including pages, followers, polls, RSS ...