Use the RES\multilang.exe wizard to generate multi-language resource file. 
It will create the frxMultiLang.pas unit with the following contents:

unit frxMultiLang;

interface

procedure SetEnglishResources;
procedure SetRussianResources;

...

You need to include this unit into your app. To switch the resources, just 
call one of SetXXXResources methods.