Answer:
First, you need to charge the battery.
You do this by connecting the device to the electricity, in this way you can store the energy, that comes in form of electric energy, in the battery, that stores the energy in form of chemical energy.
When you push the "ON" button, the energy stored in the battery starts to run in the device, in form of electrical energy, in this way it reaches all the components and the computer is fully turned on.
At this moment the Chromebook turns on its screen, producing luminous energy (so consumes the electric energy that comes from the battery, and turns it into luminous energy).
There are other transformations, for example, in the cooler (the small fan inside the device) there is a transformation from electrical energy to mechanical energy (because the fan is rotating now).