First, try to imagine the states your automaton can be in. Something like:
Off, Ready, Working
Afterwards imagine the buttons or inputs you have to perform to switch between these states. Do not forget to define every input on every state. If you leave out several transitions, the automaton is not deterministic therefore is an NFA. Transitions could be:
0 for power off/on
1 for start/stop working
Off -0-> Ready
Ready -1-> Working
Ready -0-> Off
Working -1-> Ready (4 for the actual working process)
Off -1-> Off
Working -0-> Working (nothing happens in this cases)
Just connect the states with the given transitions, and voilá!