Multi Site Set-up (mu-plugins)

Hi,

I have a network of seven blogs.

The main blog is the root directory and all other sites/directories are placed in that root folder.

Is there a folder I should have placed all the network sites into?

I am trying to use a sitewide plugin to network all posts to the main blog.

I have run into some issues and I thought maybe i set up the network structure wrong

i recently created a mu-plugins folder in the wp-content folder of the network admin and nothing is recognized in that folder

please leave me some direction