You can add or edit an announcement by going to:

 Administration ->  HR ->  Announcements

When adding or editing a new announcement you have the option to add a link to a company document. 

To do this you need to select a document using the 'Link to company document'  drop-down menu. Once a document is selected pressing the 'Submit' button will add the document as an attachment to the announcement. 

Please note: the list shows all documents regardless of their permissions so, whilst a document may be limited to one department under Company Documents this will still be eligible in the list.

Providing you have set your announcement to active, this will appear on the right-hand side of your screen. You will see a paperclip icon alongside the name of your document beneath the content of your announcement.