Not sure how to correct navigation menu so new pages show on google search

Not sure if I'm using the correct language but here's the question.  We created some new pages on our website and they show when you go the home page.  However, if you are simply searching for our website online, it is still showing old pages that have no links associated with them anymore and not showing the pages we have listed on our website.  I cannot figure out how or where to go to change that.