To start using the coding standards, you just need to checkout this repo into your CodeSniffer folder as PackagedCodeStandards
e.g. git clone https://github.com/packaged/codestandards.git PackagedCodeStandards
/path/to/pear/PHP/CodeSniffer/Standards/
e.g. /usr/lib/php/pear/PHP/CodeSniffer/Standards/
if you are running phpcs through a global installation in composer, your standards directory will be:
$HOME/.composer/vendor/squizlabs/php_codesniffer/CodeSniffer/Standards