Adding language on Wordpress

[Stefan]

Hi everyone,

When it comes to adding a new languages for a Wordpress site, I have understood that using subfolders are better than subdomains for SEO, am I correct?

What is the best procedure when adding a language in a subfolder, for example mysite.com/de/. Should WP be installed in that folder as in the root folder, or should pages be added under that "folder" as done for other sections on the site? Would this be interfering the permalink structure?

Hope it's understandable, I have just started working with Wordpress

Stefan