In which language do you want to translate the site? So I will set up that language on the site with loco then you will never lose the changes after the theme update.
Let me explain, Let’s take an example you are using English for US language on your site, and the language files are en_US.po and en_US.mo, Now rename those files as woodmart-en_US.po and woodmart-en_US.mo and place those language files under wp-content/languages/themes It will not be overridden again whenever you will update the Theme same as for other languages you are using.
I have set up the theme translation, now if you want to make any changes in the language, you should go to the links below, find the words, translate or change them and save them: