Then extract into extension directory and finally edit your config.php file and following lines in // application components section
'clientScript' => array(
'class' => 'ext.minify.EClientScript',
'combineScriptFiles' => true,
'combineCssFiles' => true,
'optimizeCssFiles' => true,
'optimizeScriptFiles' => false,
Now test using YSlow or Google Pagespeed.