CONFUSED! Multi-user help in Network?

Hi!

I am very confused on how WPMU & BuddyPress works.

I want to make the Network theme be able to take sign-ups for multiple users, and all of them create their own blogs within my domain.

However, I don't want them to have to use the WP admin bar or dashboard, but instead use a simplified user interface, like BuddyPress.

I want all the posts from the different blogs show up on the main homepage of my Network-themed site, so that my users can generate my site's content for them.

However, that's not happening, and instead when I tested my multi-site out, I end up creating an entirely separate site, that just happened to be under my main site.

Sorry if this is confusing, but basically, I want my Network-themed site to be simplefied and as separate from Wordpress as possible.

How do I do this? Thanks!