Hello!

introduction

Mozilla Developer Network (MDN) has a good series of articles describing how the internet work, in particular browsers and servers:

https://developer.mozilla.org/en-US/Learn/Web_Mechanics

After you've looked through those, try doing this course on HTML, which is the language used to describe what a webpage should contain.

http://www.codecademy.com/tracks/web
Additional resource to complement above course: 
https://developer.mozilla.org/en-US/docs/Web/HTML

Then, you can try doing this course on Javascript, which is a programming language used to make webpages interactive:

http://www.codecademy.com/tracks/javascript

The following are some more in depth programming courses:

https://www.coursera.org/course/cs101
https://www.edx.org/course/introduction-computer-science-harvardx-cs50x#.VOfuyVPF9Hh

In general, good places for introductory material:

https://coursera.org
http://codecademy.com/
https://developer.mozilla.org
https://stackoverflow.com