Adding user manual

Author: Alexander Obuhovich

README.md

@@ -8,15 +8,18 @@ Feel free to ask any questions and share your experiences in the [Chat Room](htt
 
 ## Usage
 
-...
+1. when creating unit test class sub-class the base test case class (see [Installation](#installation))
+2. use `$this->pageFactory` to get page factory instance associated with current Mink session
 
 ## Installation
 
-...
+1. run this command to add Composer dependencies: `php composer.phar require qa-tools/phpunit-extension --dev`
+2. create base class for all unit tests by sub-classing `\QATools\PHPUnitExtension\AbstractQAToolsTestCase`
+3. take a look at provided `\QATools\PHPUnitExtension\AbstractQAToolsTestCase::getBrowserAliases` method (change in sub-class if needed) to find out what default browser is used
 
 ## Requirements
 
-...
+* [Composer](https://getcomposer.org/download/)
 
 ## License