This is probably the easiest method to translate themes and plugins and tutorial shows you how to do it.
It’s going to be very quick, thanks to the “Loco Translate” WordPress plugin.

On top of that – you can also use this method to change the wording of your theme ( in buttons, labels, widgets, etc. ) without changing the language. Instead of editing code, you can use this translation technique.

Links from the video:

– Loco Translate Plugin: https://wordpress.org/plugins/loco-translate/
– Aster WordPress Theme for Photographers: http://themeforest.net/item/aster-photography-theme/12711024