docs: simplify contributing by adding instructions (#1071)

Author: martijnimhoff

.gitignore

@@ -12,3 +12,4 @@ deps/*
 .DS_Store
 
 .vscode
+.idea

CONTRIBUTING.md

@@ -13,6 +13,7 @@ so if you feel something is missing feel free to send a pull request.
   * [Contributor Agreement](#contributor-agreement)
 
 [How Can I Contribute?](#how-can-i-contribute)
+  * [Setting up the repository](#setting-up-the-repository)
   * [Reporting Bugs](#reporting-bugs)
   * [Suggesting Enhancements](#suggesting-enhancements)
   * [Pull Requests](#pull-requests)
@@ -37,6 +38,14 @@ Not currently required.
 
 ## How can I contribute?
 
+### Setting up the repository
+
+To set up the library locally, do the following:
+
+1) Clone this repository.
+2) Install librdkafka with `git submodule update --init --recursive`
+3) Install the dependencies `npm install`
+
 ### Reporting Bugs
 
 Please use __Github Issues__ to report bugs. When filling out an issue report,