Need assistance with translation procedures

[JihanLoong]

Seems the steps listed here https://github.com/subhra74/xdm/wiki/Submitting-translations-for-XDM is a little unfamiliar to me.
What confused me are:

• How to download the English language file from ?
• What is "the map file" ? How can I edit the map file? How can I save the map file in UTF-8 option?

Thank you!