How do I delete a quick link from the navigation bar at the UI ?
An as a link to a place where I can get instructions would be helpful too.
Go to transaction SPRO (IMG) > CRM > UI Framework > Technical Role Definition > Define Navigation Bar Profile. There you should be able to customize your navigation bar. Also note that this is closely related to the Business Role your using, so you should check the Business Roles section in SPRO as well.
Hope this helps,