Setting up WordPress multi language without a plugin is a complex and time-consuming process. However, here's how to do it yourself.
If this process is a bit too technical for you, you can always use TranslatePress instead and have your multilingual site up and ready in no time.
TranslatePress is a user-friendly WordPress plugin that turns your website multilingual with no technical skills required on your part.
Chapters:
00:00 Intro
00:29 Set up WordPress Multisite
03:55 Create separate sites for individual language
05:13 Link the sites together
06:04 The easier alternative: TranslatePress