How would I make a template in Notepad++? Would I just create the layout and copy the code onto a new page, then add content to each section manually? Is that how someone would add new content to their website? Like just manually code it and upload it with ftp? What do content managers do?
Content managers allow you to update your site, from site in normally a very user-friendly way. These content managers normally come with templates or a way to make a template, and then it is updated site wide. Normally all content is saved into a database and then displayed when called upon by PHP or ASP. You can make a template and update every page if you want, but is easier to set it up so you just have to update one template page and it is used site wide.
Yes you can add content to your website manually by coding... But most of people today use some CMS systems to handle it... it's much easier and you don't need to understand coding to be able to add stuff to your stuff. There are many CMS there... most used one is Wordpress but there are many others (e107, graffitti etc)