I2S Slave mode

Hello there,
How does slave mode work with I2S?

  1. Does this work as following: an external interrupt decides the sample frequency?
  2. How do you swich between L/R channel?
  3. Which pin does it read from??

void setup() {
pinMode(A1, INPUT_PULLUP);
void interrupt();
attachInterrupt(digitalPinToInterrupt(A1), interrupt, RISING);

I2S.begin(I2S_PHILIPS_MODE, 24);
}

void loop() {
//Other things happening here
}

void interrupt() {
int sample = I2S.read();
}