Editorial Tasks can only be used by users who are using Nelio Content Premium. If you’re currently using the Free Version of Nelio Content, then you won’t be able to create nor manage any editorial tasks at all.
I’m am using Nelio Content Premium, but I Still Can’t Use Editorial Tasks…
After purchasing Nelio Content Premium, you’ll receive an e-mail with a License Key. You have to add this License Key in the plugin to unlock the features that are only available to subscribers, including Editorial Tasks.