How can I see what is in my cloud??

For purchases as suggested by the support document you posted from, anything with a cloud icon with a downward arrow, is not downloaded to the devices and as such would be in the cloud. Purchases do not use storage space in iCloud directly and woulds not appear in iCloud.com

If you mean something else, then please explain.

Log on at iCloud.com or review the items that you sync on any connected device.