Setting up multisite in a directory - confusing installation manuals

I am utterly confused. I confess I have never used WP but i'm no dummy.
However, I find that somebody has not updated the multi sites installation manuals.

Where Wordpress says nothing about the blogs.dir, your installation manual mentions you don't need it at the top of the page, then below it says you should add one.

Where your manual says, "remove the earlier added define(WP_ALLOW_MULTISITE, true); line." Wordpress says NOT to remove it.

Who shall I follow?

FYI - I am setting up my multisite in a directory - http://mysite/mymultisite - for the multiple shops module.

Thank you