I attached the TranslationGuidelines.doc . But remember, that file is for Plus! v.3, so some codes may not be used in Plus! Live translation. But the logic is almost same. If you hesitate, check other translation files how they did some specific translations.
Also I'll suggest you to set the first Registry Setting "AlwaysReloadInterfaces" in
http://www.msgpluslive.net/help/registry/ before starting to check your translation on the program's interface. I used this a lot while checking mine. For example, if a line doesn't fit the specified place on the software, you can shorten it in the file, then save the file, then re-open that Plus! window. This registry setting will save you to Exit Messenger and then restart it to check every minor change in the file.