I downloaded the language package, and uploaded the files exactly following:
The following files contain additional (except in the case of English) language packages. Just extract them into the same directory as the installation of SMF.
When I log into admin panel -> themes and layout, why I can not see the uploaded language? Is ther any other thing I need to do?
I manually editted the language setting in setting.php, then it works now.
DO we have to edit on a smf code in order the implement this simple language changing task? Really hate to touch code.
no, if the language files are in Themes\default\languages, then smf should be able to detect them automatically.
You can set the default language settings from server settings in admin panel.