A HorizonScript file is, at its core, a collection of values that determine the actions and configuration values used to transform a computer from an indeterminate state to a well-known state running Adélie Linux. These values are categorised into keys, which is a logical unit of a value. This chapter defines and specifies for every valid key for a HorizonScript file: its name, its purpose, its format, and one or more example values with explanations.