add my css file to prestashop

[yaniv2266]

im new in prestashop . i create my css file and want to add it to prestashop theme. how can i add the new fill and make prestashop read the file in the header section ? in furoms i see that thy said to add it to hookheader , i tried to add it to some moudle and do the fallow:

1) add to the theme header file {hook h="myCssHook"}

2) add to some rendom module function:

public function myCsshook(&params)
{
$this->context->controller->addCSS(($this->_path).'prestashop/myshop/theme/css/myoverride/myCsstheme.css', 'all');
}

3) in the module installition copy and add:

|| $this->registerHook('myCssHook') == false

and its didnt work . im using prestashop 1.6.1.1