This video covers how to add a new referencing style (also know as an output style) into EndNote. The specific example in the video is for a Cite Them Right compatible version of the Harvard referencing style, but the method can be applied to any of the referencing styles available to download.
There will be many in the Style Manager already so if you want to use one of those you will just need to select it. But if you are looking for a style, or a version of a style which isn't already in the style manager then you can use this method to search for, and add it.