Publish and Unpublish fields of this section define the period of time when an Item can be published. They do not invoke publish or unpublish actions.
Even if content has reached the Final state of a workflow, it will not be published if the Publish date in the Publishing section has been defined but not reached, or if the Unpublish date in the Publishing section has passed. These fields are shared between all languages – there is only one publishing date per a content Item. Clearing the publishing date fields should result in the content Item being published on the next publication.
This field defines where the content will be published from the master database.
Publishing targets are defined under system/Publishing targets
Each publishing target is associated with a particular database. For instance, Internet target is associated with the web database.
This checkbox defines whether an Item will be published. If an Item has been published and this checkbox is checked afterwards, the Item will be unpublished (i.e. removed from the target database).
The publish and unpublish dates and times obey the <frequency>…</frequency> definition of the <scheduling> section of the web.config file.
Please refer to the link below to read more about scheduled tasks: