I'm using NopCommerce v4.30. The problem is that I have to implement multi-language in my nop commerce store but i'm not much familiar with nop commerce,I go through the nop documentation and, i try some of the Links that are given in nop commerce documentation and it worked for me.
Just add a new Language that you want to add by clicking on AddNew Button and after saving the language, download the language pack from the given link below and import the downloaded (.xaml) file by clicking on the import resources.
Here are the links :- https://docs.nopcommerce.com/en/getting-started/advanced-configuration/localization.html