Well designed website, though I still don't understand how it works, how would 'Decentralized Cloud Storage' be possible? I don't think you can use blockchain to transfer files or the size is gonna be huuuuuge... Explanation would be good

This is correct, you would quickly run into something called blockchain bloat, and well as some terrible legal implication. Instead we can use the blockchain to "point" to a file on the network. This also allows us to support multiple decentralized data networks.
Not sure if this has already been answered, but which blockchain are you planning to use to store your file pointers? Its not the bitcoin blockchain, is it ??