No, she didn't. People simply got in the habit of sending email to Clinton on her own server. If they didn't, her staff would forward it to her.
There was no overt connection from Clinton's server to the State Dept. insecure systems. And, there's also no direct connections between secure and unsecure systems -- everything transiting between them goes through a review process that can take at least 24 hours.
Seems like whatever system the SoS uses, it’s still part of the Dept. of State’s overall system.