How do I store things on iCloud?

iCloud seriously confuses me, it’s such an abstract concept. I want to free up space on my MacBook because the startup disc is almost full. Can I sync my movies onto my iPod, then delete them off iTunes but store them in the Cloud? Is there any way I can do this?

When I go to the iCloud icon in system preferences, it lets me check off things like mail, contacts etc. However, there is no place for movies. I think checking these off means that they will automatically downloaded between my devices. But, I want to use iCloud to store heavy files such as whole TV seasons (these are usually 10 GB!). How do I choose what to store? The Apple website is absolutely no help…