You use the Virtual Switch Manager
While you can create a virtual machine without a virtual network connection and then add it later, you'll want to have it in place before create your first virtual machine. You'll use the Virtual Switch Manager to create and configure how you want the virtual network connection to work.
After you launch the Hyper-V Manager, navigate to the Actions pane and select the Virtual Switch Manager action.
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Greg Shultz is a freelance Technical Writer. Previously, he has worked as Documentation Specialist in the software industry, a Technical Support Specialist in educational industry, and a Technical Journalist in the computer publishing industry.