Language selection on TP177B

I made a project with Step7&WinnCC flexible.My customer want second language ( Russian )also .How can I make this very simply?.I saw a project that A button assigned on screen ( with country flag picture).Which language do you want on screen,then the push this button is enough.But no backup.Thanks in advance for any help.

The help in Flexible is pretty good - take a look under "Multlingual User Interface".

Here is quick & simple.
In your project tree scroll down to Language Settings - Project Languages.
Check what you want.

Options - Texts - Export.
It will generate some .csv files.
Then open Excel and do File - Open - and open a .csv file.
You'll have a column for each language.
The translator fills in the language text.
Save .csv and Import.

You will find the fonts for the texts will have to be adjusted on an as-needed basis.