EcoDash requires HomeAssistant to run. Its purpose is translating the protocols that different smart plugs use into a simple universal HTTP API that EcoDash can use.
Install HomeAssistant: follow this guide. The installation method you choose doesn't matter.
Add your smart energy monitor. Go to Settings -> Devices and Services -> Add Integration -> Choose your device type. Follow this guide for Zigbee devices.
Generate an API Key for EcoDash:
Go to your profile (bottom left of the page - click on your account name)