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If you face a problem with translation, you need to be sure that your translation files are synchronized. After synchronization, you will be able to find and translate the required strings. Make sure you placed translation files into the /wp-content/languages/themes/ folder with correct names (language name and xstore theme suffix, e.g xstore-nl_NL.po, xstore-nl_ML.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. Read more – https://xstore.helpscoutdocs.com/article/30-base-theme-translation
Please read this article – https://codex.wordpress.org/Child_Themes
If you want to make changes in cart.php (wp-content/themes/xstore/woocommerce/cart) you need to copy the file into child-theme/woocommerce/cart folder.
If you want to change function, for example, etheme_sign_link (wp-content/themes/xstore/framework/theme-functions.php), you need to copy the function into functions.php file of the child theme.
Feel free to ask if you have any other questions.
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