I have pretty much no knowledge in coding but pick up what I need along the way.
The best advise I could give you at this point is "Stop!". Go study coding. http://www.w3schools.com/
What your asking is basic and definitely needed for a 80-90 page site that your just going to be coming back here asking question all the time. Study, learn; You'll be happier and things will go faster for you.
Loading a header into a div with a require('./header.html'); is also used for the footer and nav column in most cases.