This page used to walk through building the embed code by hand, one example at a time. That walkthrough has been replaced by two better options:
Open the Webmaster Code Builder → Download the Full Reference (PDF) →
The Code Builder is logged-in, point-and-click, and shows you a live preview of your real schedule as you go — use this if you just want your code. The PDF reference documents every option available, including a few advanced ones the Code Builder doesn't offer a control for yet — use this if you're hand-editing code or want the full picture.
Both are also available any time from the Webmaster Tools section of the user menu while logged in.