EndNote has a very good user's guide, which comes with the programme, and which is also available via their website.
Wageningen UR Library made a short manual which exactly shows how to transfer information from bibliographic databases to your EndNote library. It is available as an HTML and PDF version.
The library also offers short introduction sessions and courses for beginning and advanced EndNote users.
More information on EndNote can be found on the library website (http://library.wur.nl/endnote). For specific questions on EndNote, contact servicedesk.library@wur.nl.