By the way, as Administrators (Operators with administration privileges) you all have unrestricted access to others' campaigns. Marketing business users would not typically have this level of access. Click on the image int he previous to see a much clearer version.
Thanks for asking this question! "Assigning the campaign" is a reference to the Campaign Manager or in French "Responsible". The Campaign Manager is typically the person to start the workflow that executes the campaign. This Operator (user) has the ability to approve steps in the campaign in addition to any designated approver(s). And they should be the one to Confirm the delivery. To set this property:
When you create a campaign template, you should null out this field. Then the campaign is automatically assigned to the person who is creating the campaign. However if that person wants to designate another Campaign Manager, perhaps someone from marketing operations, they can use this screen to do so.