You can add your own levels to a collection, see the amount of visitors, subscribers and positive/negative ratings, and add a more in-depth description than what the level editor allows.

Not only that, you can create your own forum threads (each Workshop item and each collection have their own forum where you are the moderator!).

It also makes it easier to keep track of your creations, and people can subscribe to your content. You can also create collections of other people's levels that you enjoy.

So while it's not possible to create episodes with a main map, you can still use a Workshop collection to make your own pseudo-episode.

If you need some help getting started with the Steam Workshop feel free to reply in this topic.

Here's an example of what it looks like, the forum of Rig 17, my episode-sized level set.

You can get to the Collections section of the Workshop by using the tab in the CC:HD level browser, HERE.