Hello,
I can’t to copy translation file to my theme. According to the ticketbox guide, first i have downloaded tool POEdit, second opened it and loaded, third i translated text and saved file. Forth I renamed it with code name of my language. Finally I couldn’t find WPLANG.
When I read a documentation, it has written there is only has WPLANG at WordPress version 3.9. But My WP Version is 4.9.1.

So please help me to resolve this issue.

Thank you.