Can't install WP MU Plugins - following all directions, nothing is happening!?

I'm a newbie to wp-mu, but not webdesign in general. I've been reading, following instructions, retrying, etc. to get the wpmu plugins to install. I've read the articles about how to install, I've followed directions, checked file directory permissions, etc. Still can't seem to get them to work. What am I missing?!!!

As I understand it, you place the files in appropriate directories (most wp-mu plugins) as indicated by directions. Once uploaded, the plugin is automatically activated. Is that correct? Then you should see it under your wpmu-dev panel in the admin side -

Plugins aren't there. Any help would be really appreciated!!

Today I have worked on installing the avatar plugin, and the members directory plugin.