For multi-lang, how to rename a page file via Admin Panel?

Hi, according to the Grav doc (https://learn.getgrav.org/content/multi-language#multi-language-basics), the language of a given page is specified via the file name, eg:

docs.en.md
docs.cn.md

I use the Learn 2 theme, and my question - how can I rename the md file via the Admin Panel, so that I can specify the language for a page? Thanks!

In the admin panel you don't rename the file, you just pick a language to save it in. The admin panel will rename it appropriately.

Hi rhukster,

Thanks for your answer - although I've been working in the software development area over 10 years, and I tried over ten times, I couldn't find where to pick the language for a given page, can you tell me exactly the position? Thanks.

You need to add the supported languages. In the admin this is done by editing the System Configruation, but I always use the files :)

I actually did added two supported languages – en and cn, but still couldn't find where to pick a language, I attached several screenshots demonstrating the problem, any ideas? Thanks again!
2016-04-27_13h06_33

If a page is already translated, you won't see a button to translate it in the Page detail. You switch the language in the Pages list.

Screen Shot 2016-04-27 at 10

Otherwise if a page is, say, in english, but has no other language, you'll see a "Save as <language>" if you click the arrow next to the Save button, up right in the page.

Thanks flaviocopes, so I tried the 'save as' menu, now I can:
1 - set an 'untranslated' page as one of the available languages, and,
2 - switch a 'translated' page to another available languages.

But how can I copy a 'translated' page as a new one for another language? I noticed the 'Copy' button at the top, but obviously it is 'copy as another page' but NOT 'copy as another language'.

Should have a dropdown in your save button so you can pick "save as <language>"

Thank you two guys! I see now - I can switch languages via the button at the upper right corner in the 'Manage Pages' page, as shown to me by @flaviocopes, but since I used the wrong language id "cn" ( I should have used "zh-cn" instead, so I didn't see Chinese was listed when @flaviocopes pasted his screenshot!

But I've got a new question now - the URL of my site:
truesimplesoft.com/zh-cn

the "zh-cn" subfolder is a bit complex, how can I use 'cn' instead? Thanks.