Data can be uploaded in variety of ways. It looks like anywhere you can add and edit text there is also an option to attach multiple files. They need to be smaller than 128 MB. For example, this blog entry has a file attached. Simple pages can have attached files as well. Another option is to use the class app and attach files as class materials. Files there need be smaller than 256 MB. Software uploads could also be used to distribute files. This option has the advantage of having a way of versioning data sets. Files size is up to 256 MB there as well.