For non-preemptive system,
waitingTime = startTime - arrivalTime
turnaroundTime = burstTime + waitingTime = finishTime- arrivalTime
startTime = Time at which the process started executing
finishTime = Time at which the process finished executing
You can keep track of the current time elapsed in the system(timeElapsed). Assign all processors to a process in the beginning, and execute until the shortest process is done executing. Then assign this processor which is free to the next process in the queue. Do this until the queue is empty and all processes are done executing. Also, whenever a process starts executing, recored its startTime, when finishes, record its finishTime (both same as timeElapsed). That way you can calculate what you need.