Trouble understanding Motor Shield

I have an Arduino Motor Shield R2 and am trying to read the current draw on the motors as they are running.

Questions:
The SNS0 and SNS1 are sent to the A0 and A1 one pins automatically correct? or do I need code to tell it that?
I can read the A0 and A1 using analogread() do I need any other code?
Do I need to connect 3.3V to the AREF input?

My motors are working correctly, changing speed as the pwm value changes and that is showing up on my LCD screen. However I expect the current to the motor to also change but the value is not being updated on the LCD screen.

I borrowed this code from this post "Arduino Motor Sheild & DC Motor"

Code as follows:

#define DIRA            12                  // Direction motor pin
#define DIRB            13                  // Direction motor pin
#define PWMA            3                   // PWM motor pin
#define PWMB            11                  // PWM motor pin
#define BREAKA          9                   // Break A
#define BREAKB          8                   // Break B
#define CURRENTA        A0                  // Current Sensing A
#define CURRENTB        A1                  // Current Sensing B

#include "SoftwareSerial.h"
const int TxPin = 6;                  //Output signal to LCD
SoftwareSerial mySerial = SoftwareSerial(255, TxPin);



int PWM_val = 0;                                // (25% = 64; 50% = 127; 75% = 191; 100% = 255)
int Val1 = 0;
int Val2 = 0;


void setup()
{ pinMode(TxPin, OUTPUT);            
   digitalWrite(TxPin, HIGH);
   
  mySerial.begin(9600);                //Transmit at 96000 baud
  delay(100);
  Serial.begin(9600);
   
    mySerial.write(17);                // Turn backlight on
    mySerial.write(22);                // disable cursor disable blink
    mySerial.write(12);                // clear screen and place cursor at upper left corner
    delay(5);                          // Required delay
  
{
 // analogReference(EXTERNAL);                            // Current external ref is 3.3V
//  Serial.begin(115600);
  Serial.begin(9600);
  pinMode(DIRA, OUTPUT);
  pinMode(DIRB, OUTPUT);
  pinMode(PWMA, OUTPUT);
  pinMode(PWMB, OUTPUT);
  //pinMode(CURRENTA, INPUT);
  //pinMode(CURRENTB, INPUT);
  //digitalWrite(CURRENTA, HIGH);                     
  //digitalWrite(CURRENTB, HIGH);

  analogWrite(PWMA, PWM_val);
  analogWrite(PWMB, PWM_val);
  digitalWrite(DIRA, HIGH);
  digitalWrite(DIRB, HIGH);
  delay(500);
} /* setup */
}

void loop() {

  for (PWM_val = 0; PWM_val <= 255; PWM_val = PWM_val +10)
  {
    analogWrite(PWMA, PWM_val);                                               // send PWM to motor
    analogWrite(PWMB, PWM_val);
    analogRead (CURRENTA);
    analogRead (CURRENTB);
    mySerial.write(128); 
    mySerial.print("PWM:");
    mySerial.write(133);
    mySerial.print(PWM_val);
    mySerial.write(148);
    mySerial.print("AMP:");
    mySerial.write(154);
    mySerial.print(CURRENTA);
    mySerial.print("\n");
      delay(500);
  } /* for */

 } /* loop */

To answer my own questions

The SNS0 and SNS1 are sent to the A0 and A1 one pins automatically correct? or do I need code to tell it that?

No

I can read the A0 and A1 using analogread() do I need any other code?

No

Do I need to connect 3.3V to the AREF input?

Yes