How to change keyboard & display language in Windows 10.

To change display language in Windows 10:

Click Start, Settings, Time & Language,
Click Additional date, time, & regional settings,
Click change input methods, options,
Click add a language, select your language,
Click add, in your new added language click options,
Click Download and insall language pack.
Wait a few moments until language files are downloaded and installed, when installaion is finished clik Restart Now.
After the Computer restarts click Start, Settings, Time & Language, Region & Language, click in your language, click Set as default, your display language will be changed afer next sign-in.

Click Start, Settings, Time & Language, Additional date, time, & regional settings.
Click change input methods, options, add an input method.
Click in your favorite keyboard language.
Click add, click save.
Now switch to your language in left side of toolbar.