changing existing website

Hi! I'm new to this, so I need some help! I have an existing website but I'm trying to update it. I've created some new pages and uploaded them into smartftp, but I can't get to them to show up online or to override the existing pages. Any help? Sorry if this isn't specific enough, let me know and I'll post more details, but like I said I'm new to this!

Thanks so much!
-roial