Update CONTRIBUTING

CONTRIBUTING.md

@@ -1,7 +1,12 @@
 # Contributor guidelines
 
-You can [open an issue](https://help.github.com/articles/creating-an-issue/) and give us your suggestions as to how we can improve this guide, or what we can do to improve the learning experience.
-
-You can also [fork this project](https://help.github.com/articles/fork-a-repo/) and send a [pull request](https://help.github.com/articles/using-pull-requests/) to fix any mistakes that you have found.
-
-If you want to suggest a new resource, send a pull request adding such resource to the [extras](https://github.com/open-source-society/computer-science/tree/master/extras) section.
+This project primarily uses GitHub for collaboration, however not all discussions are appropriate for GitHub.
+Please follow these guidelines:
+1. If you need help with the *academic* content of a course or are having general technical difficulties, please do not use GitHub for this.
+The best place to ask these types of questions is on the [subreddit](https://www.reddit.com/r/opensourcesociety/).
+2. If you have general problems with the program not specific to any course, such as preferring textbook-style learning over MOOCs,
+the subreddit is recommended as there people may be able to give you suggested alternatives.
+3. If you have *specific* and *substantive* criticisms of the curriculum, i.e. problems related to the progression/content of courses it would be appropriate to [open an issue](https://help.github.com/articles/creating-an-issue/) and give us your suggestions.
+4. If you have *non-substantive* updates to make to the curriculum, such as a course's URL having been moved, spelling/syntax errors, etc., please send a [pull request](https://help.github.com/articles/using-pull-requests/) to fix any mistakes that you have found.
+5. If you want to customize the curriculum for yourself, do of course [fork this project](https://help.github.com/articles/fork-a-repo/).
+6. If you want to suggest a new resource, send a pull request adding such resource to the [extras](https://github.com/open-source-society/computer-science/tree/master/extras) section.