How to Set Up WordPress Multi Language without a Plugin (And an Easier Alternative)

I have an issue:
1- the plugin add the English text although I translate it!!
2- I tried to use the tag <br> to start a new line with particular word but it doesn't.

Really useful, thanks

I followed the steps from this tutorial and now I'm unable to add new plugins to my existing main domain, what is this?

I think you also forgot to show to install WordPress on this new subdomain?