When launched for the first time, Home Assistant will write a default configuration file, called
configuration.yaml, enabling the web interface and device discovery. It can take up to a minute for your devices to be discovered and appear in the user interface.
configuration.yaml is written in YAML, stored in
.homeassistant, and can be modified with a text editor.
See the components overview page to find sample entries for your devices and services. For a sensor that is showing random values, the entry would looks like the sample below:
- platform: random
The Setting up devices part contains of the documentation additional details about adding device and services and customization.
For further details about configuration, please take a look at the configuration documentation.