Hi esnagel,
You'll first need to create a signup form in AWeber at the
Web Forms page.
Then, take the JavaScript you're provided after doing that and edit the Layout menu in Blogger. Add an HTML/Javascript gadget to your sidebar, and when prompted, paste in the JavaScript and save.
Hope this helps! If you have any other questions, please
contact us - we'll be happy to assist by phone, email or live chat.