How can i make multi-language site? [closed]

I've got a question. How can I create a site in multiple languages? Actually I am building a site in EJS and am going to make it multilingual.

I would like the system to work on the principle that after selecting the language it changes:

• Flag in the selection menu,
• Country name or prefix in the selection menu,
• Full page content in each language.

I would also like to change the language on each subpage the user navigates to after selecting the language.