Please read our documentation https://xstore.helpscoutdocs.com/article/30-base-theme-translation
Likely you simply need to synchronize translation files.
Make sure you placed translation files into the languages /wp-content/languages/themes/ folder with correct names (language name and xstore theme suffix, e.g xstore-de_DE.po, xstore-de_DE.mo).
Button Sync (Loco Translate plugin http://prntscr.com/glemdq) allows you to synchronize your translation file with updated pot file. It means if we made any changes in template files that may affect transaltion or we added new string for the translation and you updated theme you need to synchronize your translation with updated files. Only after synchronization, you’ll be able to translate new strings or strings that were changed.
