In these tabs you can keep information which should be linked to the opportunity:
Use the Docs tab to link documents associated with the Opportunity.
Use the Message (Msg.) tab for internal messages that have been transferred between team members and are relevant to this Opportunity. You can use this tab to send other employees internal messages which relate to this opportunities.
Use the Notes tab to keep internal notes regarding this sales opportunity.
To add new documents or messages to this Opportunity, click the New button at the bottom of each tab’s window.
Creating a new Document for the Opportunity