If you go by public transport the next website can give you directions for train traveling in the Netherlands.
www.ns.nl click on English in the right hand upper corner and you will find a menu for travel directions by train. Your end station is Den Helder.
From there you have to take bus number 33 to the ferry. You want to arrive in Den Helder 4 minutes before the hour, so you can catch the bus from quarter past and the ferry from half past the hour. More information can be found on www.teso.nl