Drupal Mulitsite

I’ve looked at this page and this site but I’m still a little confused as to what/where I should symbolically link.

I have drupal installed in a subdir called (for example) sub.dir.com and then I have 2 sites I want to run, site_1 and site_2.
Where woud I place my links? In sub.dir.com or in my home folder (one directory above)?
Would the code be
ln -s sub.dir.com site_1
ln -s sub.dir.com site_2 ?

I seem to be doing everything right but I still can’t get Drupal multisite running.

Nobody can help me?
I am sad.