To change the settings of the BrandsSync app go to 'App' from the side menu of the Shopify dashboard and select 'BrandsSync'.
From the side menu click on 'Settings' and you can change the general settings.
Remember that to change the import language and the product-related settings you must first delete all already imported products.
If you need assistance to eliminate all products, consult this question.
To follow the different steps to change the app settings watch this video