mechatronics. the code has to work without the 9volt battery. i need a code . i cant seem to figure out how to make it work. do not use arrays

Problem: Build the circuit given below and write a program that achieves following functionality. Button is used for power on/off of the whole system. Potentiometer is used to control the speed of the DC motor and LED turns on when system is on otherwise stays off. Circutit