Hikashop Multi language

-- HikaShop version -- : 1.5.6
-- Joomla version -- : 2.5.1

-- HikaShop version -- : 1.5.6 Business Edition
-- Joomla version -- : 2.5.1

Hi,

I have plan to make my site multi language English and German. Right now its in English.
So when with language selector if some one select German language then all content change to specific language like

category, products, products detail page, checkout page and when placeing order then user get emails and invoices

in language which he selected while placing order.

So please guide me step wise how I make it, some Tutorial and helping material.

Thank You