I think I've set up Multisite wrong?

Hello,

I wanted to use Multisite so that I could design some WordPress templates separate to my own theme. It seemed easier to use MultiSite than the subdomain option through my server. I followed the instructions on how to install multisite and have added a new Site to my website, but I can’t seem to do anything on it. When I click ‘dashboard’ it goes to my internet service provider ‘website not found’ page.

Any help would be greatly appreciated!