Please read our documentation – https://xstore.helpscoutdocs.com/category/18-theme-translation
To make site multilanguage, you need to use one of the additional plugins:
1) WPML(paid) https://xstore.helpscoutdocs.com/article/31-translation-with-wpml
2) qTranslate(free)
3) Polylang(free with paid extra options)
If you want to translate the site to one language just use Loco translate plugin. Note that translation files should be placed in /wp-content/languages/themes/ folder with correct names (language name and xstore theme suffix, e.g xstore-de_DE.po, xstore-de_DE.mo).
Feel free to ask if you have any other questions.
