Books and even book series have been dedicated to each of those questions. Planning is the best way to go about getting started. Decide what you want to do and write it out on paper first. what pages, what functionality, what purpose you want your site to serve. Once you've done that, you can go about creating the functionality and components, and learning as you do it. If you're like me and don't have a specific site in mind, you can always just start learning. I help out on forums like this one, and openstudy.com because I find myself looking up things that I wouldn't have for myself to solve problems that others are running into.
One thing you should study further into if your book covered database interactions with mysql_ or mysqli_ is PDO. There are soooooo many old or free resources out there that people still use to learn that make use of deprecated functions.
If you want to learn for web programming, start with w3schools.com. they have primers and references for all of the major web technologies that you'll need. and if you want to learn more about computers or programming in general, MIT has made hundreds of their courses available for free online at ocw.mit.edu