Commands fall into two categories: navigation and actions.
Navigation commands such as "move right" or "move left" will act much the same as a touchpad swipe in those directions. These are associated with a standard keyboard key press. Action commands such as "take a picture" or "go to sleep" will perform a specific action that does not map to a keyboard key press. These will do more complex actions, like launching an app or putting the device to sleep. Some example commands are listed below:
Navigation: move left, move right, go back, go home, select this
Action: take a picture, start recording, go to sleep, get assistant
A full list of commands is available in the Speech Recognition page in the Settings app, or in the Speech Recognition section of the Settings tab in the Blade Companion App.