Site content is produced by creating items within a module already placed on a page. While each module is designed to manage different types of content, most modules operate in a standard standard fashion with regards to their items/content.
Add Item - this link is used to create a new module item. There may be several of these links located within the module to insert a new item into a specific location or order within all the module's content.
Edit Item - this link is used to edit and existing module item. The display in most cases is similar to the 'Add Item' display for that module.
Copy Item - this link is used to create a new item based on an existing module item. The display in most cases is similar to the 'Add Item' or 'Edit Item' display for that module. In most cases the title and body content are duplicated from the original item, however the dates and SEO information will have been initialized.
Delete Item - this link is used to remove an existing module item.
Order Items - though only displayed when manual ordering or `rank`ing is enabled, this link brings up a window with a a list of all module items which allows the user to establish a new sequence of items. Dragging an item to a new position in the list and then hitting the 'Save' button will reorder the list. This link will only be available for modules which have been configured to 'sorting by `rank`' and then only if more than one item exists.
Manage Comments - (only appears when viewing item) this link allows you to manage all module items' comments. You may edit, delete, approve or disapprove comments within the module.
Manage Tags - this link allows you to manage all module items' tags. You may add or remove tags from items in bulk. This feature may optionally be disabled for the module.
Manage Categories - this link allows you to manage all module categories and module item categories, which allows items in that module to be 'grouped'. You may assign/reassign categories to module items in bulk. Each item may optionally be assigned only one category. Categories must be created before they can be selected, and are specific to a single module type. Modules with the category feature have special views which functionally group items by category in various ways (list headings, accordion sliding, tabs, etc...) Item categories are specific to a module in nature.
Merge Item - this link is available with aggregated items and serves as an indication the item is actually contained in another (aggregated) module. It also allows the user to 'move' the item into the current module.
You can find module specific information here.