Drupal 8 Install Error - Important Links and Roles Disappear

Playing with a Drupal 8 install for the first time, I decided to just go the "grungy" route and do the minimal install. After all, I'm a DRUPAL Developer.. and I know the ins and outs of it. Not just a PHP Developer that supposedly knows everything...

Whatever, the nightmare started when I made that decision.

The install was clean and all the errors you would normally get (file permissions, create settings.php, etc) came up as expected.
Expecting that user "1" would have admin rights was a huge miss. I hope to keep you posted on this if i dig back into it... but here's what happened:

I went looking for the normal links to get started building out my site: Create Content, Create Content Type, Add User, Create User Roll... All of them GONE. ???

What I discovered was, after reinstalling and retracing such steps, that the availability of such links are heavily based on the theme. I had downloaded and installed "Professional Responsive Theme 8.x-1.0" which looked awesome in the window. But felt a bit "tight" when I tried it on. Apparently, it's not meant to be an admin theme at all... but it appears to have admin theme settings.

I may be totally wrong about this, in fact. but I've had to install and use Seven or the default theme to see the links I need to actually do "work" in D8. I don't think I ever saw this happen in D7... totally makes sense to have a change in theme still be sure to offer up such important menus / menu items. I suppose this is a security enhancement or just a way to ensure that you can turn certain things off in production sites... or if you simply don't need them for whatever other reason.

Anyway, this will surely be an interesting journey as I wish to be the overwhelming push to use D8 at my job and personally.