Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -1,3 +1,30 @@
-# Contributing #
+Contributing
+============
+
+The document covers the basic process for contributing to the [ASP.NET Core documentation site](https://docs.asp.net). For information on contributing to ASP.NET Core source, see [ASP.NET Core contributing guide](https://github.com/aspnet/Home/blob/dev/CONTRIBUTING.md) .
+
+## Contributing process
+
+Small changes to one *.md* file can be made in the browser by tapping the **Edit** link in the upper right corner of the browser window (you might need to expand the **options** in small browser windows). For new articles and changes involving more than one file:
+
+* Open an issue describing the article you wish to write or update. Get approval before you invest too much time.
+* Fork the [aspnet/docs](https://github.com/aspnet/Docs/) repo and create a branch for your article.
+* Write or update your article using [DocFX](http://dotnet.github.io/docfx/spec/docfx_flavored_markdown.html#code-snippet) in [GitHub Flavored Markdown](https://guides.github.com/features/mastering-markdown/). Images go in the *\<article-name>/_static* folder. Code goes in the *\<article-name>/samples* folder. It's often helpful to review an existing article to use as an template (for example, *tutorials\first-web-api.md* and the assets in *tutorials\first-web-api*). See the [style guide](./aspnetcore/contribute/style-guide.md) for more details.
+* Submit a pull request (PR) from your branch to `aspnet/docs/master` and respond to PR feedback.
+
+## Build and test your article with DocFX
+
+* Download and unzip *docfx.zip* from [DocFX releases](https://github.com/dotnet/docfx/releases). Add DocFX to your PATH.
+* Build and preview your changes with [DocFX command line](https://dotnet.github.io/docfx/tutorial/docfx_getting_started.html#2-use-docfx-as-a-command-line-tool). Navigate to the aspnet folder (which contains the *docfx.json* file) and enter the following in a command prompt:
+
+   ```
+   docfx -t default --serve
+   ```
+
+   The command above starts the preview on localhost:8080 where you can view the updated content in your browser.
+
+Notes:
+
+* Currently DocFX requires the .NET Framework on Windows or Mono (for Linux or macOS)
+* The local preview currently doesn't contain themes or render table correctly; the view will differ slightly from the published site
 
-For information on contributing to this repo please see the .NET Core [Contributing Guide](https://github.com/dotnet/core-docs/blob/master/CONTRIBUTING.md).