1) Login to your Wordpress Admin, and locate your Mediavine Control Panel settings via the Settings menu.
2) Click the "Log In to Mediavine" button.
2) If you aren't already logged into your dashboard, it'll prompt you to enter in your username/password.
If you ARE logged in already, it'll just take you to the Authorization screen:
4) Click "Allow".
Your Mediavine Dashboard is now connected to your MCP plugin!