1. First of all, what you want to add should be actually 'Free'. Don't mistake "An easy link to Download a book" with "Free".
2. If you don't know how to work with git or github, just simply go to [Wiki: Contribution](https://github.com/vhf/free-programming-books/wiki/Contribution) and read the rest.
+ **Books** : PDF, HTML, DJVU, ePub, a gitBook.io based site, a Git repo, etc.
+ **Courses** : A course is a well designed learning material which was made by an organized group and is availabe for a long time where there is no interactive tool embeded in the site. e.g.: [OpenCourseWare](http://ocw.mit.edu/), [PHPAcademy](https://phpacademy.org), etc.
+ **Interactive Tutorials** : An application which helps you learn, by actually typing syntax. e.g.: [Codecademy](http://www.codecademy.com/), [Try Github](http://try.github.io/), etc.
4. We prefer small commits rather than one large commit in a pull request. If you don't have the time to make small commit, add an issue with all the links included and we'll add them for you.
5. Use our standard for formatting the .md file. Check it out: [Formatting](#formatting)
+ All the lists start with an Index, the idea is to show all of sections and subsections there, so it's important to have an index for each section. Right now it's alphabetized, so please use alphabetic order.
+ Sections are using level 3 heading (in HTML is `<h3>`, in Markdown is `###`), and subsections are using level 4 (in HTML is `<h4>`, in Markdown is `####`).