After you have translated the label values in the resx files you will need to save the files in the proper naming convention in order for the language localization to work correctly.
For example, if you have translated the Step1.ascx.resx resource file in the \desktopmodules\Smith.BuyNow\App_LocalResources folder you will need to save it according to the following file naming convention that applies to your locale/language.
Step1.aspx.resx This is the default local resource file (the fallback resource file) if no language match is found.
Step1.aspx.es.resx This is the resource file for Spanish.
Step1.aspx.es-mx.resx This is the resource file for Spanish (Mexico) specifically.
Step1.aspx.fr-fr.resx This is the resource file for French.
Step1.aspx. de-de.resx This is the resource file for German.
The base name of the file matches the page file name, followed by a language and culture name, and ending with the extension .resx. For a complete list of culture names, see the following link http://sharpertutorials.com/list-of-culture-codes/
You are welcome to contribute your translated resx files back to the SmithCart community and they will be included in the next build of the cart so you can take advantage of future upgrades. You can email a zip file of your translated resx files to support@smithcart.com.