[interchange-i18n] How to start with Japanese translations?

[Interchange User]

Hi, I'm new to this need to translate our site to display Japanese 
(ie, text description and all) for both the public store and the 
admin module.  Like to know how I can kick-start in equipping myself 
with these knowledge, esp in the following areas:

1) What are the major steps to kick-start?  I assume the following:
	- add UI_LOCALE in ui.cfg
	- edit locales/ja_JP.cfg accordingly to all the English text we're 		
	  using?
	
Is that it?  Am I in the right track?

2) I saw in admin/login.html that we need to add UI_LOCALE in ui.cfg 
for the language selection list box to appear at the admin login 
screen.  I've tried adding this line to ui.cfg (I'm using v4.8.5):

Variable UI_LOCALE       ja_JP

but still the selection box did not appear.  Is that the correct way?


Much thanks for any pointers!!