What is the best ways to Test what we translate to Arabic.

and if we can change and edit translation live on koha and then export po file from koha ? 

or we have always translate in Pootle then export , then install translation 

some words we can not give it the right meaning if we do not know its Context in the system .

and I want to ask about pref.po file how to add this file to koha After installation 

I found this link but it is not explain about pref po files : 

wish you help me :)

thanks a lot .

Karam