Building Websites

There are plenty of platforms upon which you can build your own website for free. Below three of the big players in this space.
The best way to learn is to jump in and have a go! 
Play around with templates - Don't worry you can't do anything 'wrong!'

Create a Google Site like the one you're looking at right now. (if you don't have one already, you'll need a Gmail account)
Create a Weebly Site (Very intuitive - drag & drop)