Need a hidden space to learn Confluence

Hello Adaptavist...

My company has asked me to build out a new environment, and I'm completely new to Confluence. I'm familiar with wikis in general and very experienced with HTML-CSS-Javascript (which I realize should be added only sparingly, and only if I find the built-in tools somehow lacking).

My company's Confluence wiki is fully live and visible to customers, so I'm intimidated about experimenting and learning. Question: starting at the main Dashboard, how can I create an entirely new Space (call it Sandbox) that is visible (even on the Dashboard) only to me? The second question will be, once I've created a few mock-up pages and menus there, how to expose it only to company insiders and not customers?

I don't even want anyone to see it as a disabled menu item on the dashboard.

Many thanks! What I've seen so far in your documentation says that Confluence can do all we need it to do, it's just a matter of active learning (= making mistakes for a little while) in a live environment.

Cheers

Rob