You can modify the input tape by adding new rows and chaning the bits. You can also adjust the states of the machine by creating new ones or modifying the rules for the existing ones. There must always be a `start` and `halt` state.
The machine starts at the first location on the tape and start state. It then compares the transition condition to the tape and moves to a new state while updating the location it is looking at on the tape.
The output of the machine is the state of the tape at the halt state.