Lol, I'm no expert in Russian, but I think this has been answered before. You can try installing Russian language packs from the Play Store or changing your keyboard layout settings manually in the device settings. Someone please translate for me, I'm curious to know if it's more complicated than that
Lol, не проблема! You just need to go to Settings > Language and Keyboard, select Russian as your language, and then choose the keyboard layout you want. Also, check the "Enable keyboard layout switching" option, so you can easily switch between languages.