how to translate the plugin

hi,
i use the .pot file in language folder and translated with poedit.

it doesn’t work,
i renamed the translated file in it_IT and wp-hotel-booking_it_IT but still doesn’t work.

i added the define(‘WPLANG’, ‘it_IT’); string in wp-config but still doesn’t work.

how to translate it? does w3total cache effect the translation?

thank you.