How To Using PID with 3 sensor SRF04 (Front Right and Left)

it's the code from example PID.. Please Help Me..

#include <PID_v1.h>
//Define Variables we'll be connecting to double Setpoint, Input, Output;
//Define the aggressive and conservative Tuning Parameters
double aggKp=4, aggKi=0.2, aggKd=1;
double consKp=1, consKi=0.05, consKd=0.25;
//Specify the links and initial tuning parameters
PID myPID(&Input, &Output, &Setpoint, consKp, consKi, consKd, DIRECT);
void setup()
{
Serial.begin(115200);
//initialize the variables we're linked to
Input = map(analogRead(0), 0, 1023, 255, 0);
Setpoint = 650;
myPID.SetOutputLimits(0, 255);
//turn the PID on
myPID.SetMode(AUTOMATIC);
}
void loop()
{
int sensorValue = analogRead(0);
Input = map(analogRead(0), 0, 1023, 255, 0);
double gap = abs(Setpoint-Input); //distance away from setpoint
if(gap<10)
{ //we're close to setpoint, use conservative tuning parameters
myPID.SetTunings(consKp, consKi, consKd);
}
else
{
//we're far from setpoint, use aggressive tuning parameters
myPID.SetTunings(aggKp, aggKi, aggKd);
}
myPID.Compute();
analogWrite(3,Output);
Serial.println(sensorValue);
}

What changes have to done in code so we can set point from input values? And Please help me so this code works for me.

What changes have to done in code so we can set point from input values?

What input values? There is nothing in the code you posted that reads any ping sensors.