Quote from Blizzard's Blog
Much like our own universe, the StarCraft II community site is constantly expanding. We'd like to welcome you to visit our brand-new Maps and Mods page.
The Maps and Mods page will be updated with new features in the future, including details on official Blizzard mods as well as tutorials for various StarCraft II Editor modules. Whether you’re an aspiring map designer or a seasoned veteran with a few mods under your belt, our most recent StarCraft II Editor tutorial should help you take your mod making to the next level. The first entry covers ground on the Terrain Module, while our Map Publishing page will show you exactly how to get your content on Battle.net.
The Maps and Mods page will be updated with new features in the future, including details on official Blizzard mods as well as tutorials for various StarCraft II Editor modules. Whether you’re an aspiring map designer or a seasoned veteran with a few mods under your belt, our most recent StarCraft II Editor tutorial should help you take your mod making to the next level. The first entry covers ground on the Terrain Module, while our Map Publishing page will show you exactly how to get your content on Battle.net.
They explained the Terrain Module here and created some good looking terrain. So the tutorial is worth reading. They also tell you some of the super useful hotkeys. Here is the link.
They also made a small tutorial how they explain how to publishing your map and mods. You can find it here.
