Serial LCD commands

Hi! I've bought an lcd05 serial display and I'm reading right now the datasheet (http://www.robotshop.com/content/PDF/datasheet-lcd05-20-4-green.pdf). I don't understand how to write the set Cursor serial command. Should I write:

Serial.write(0x03, 1,0);

in order to write on the second row? OrI have to write 2 different commands like:

Serial.write(0x03);
Serial.write(1,0);

?

two ways according to PDF

void LCDSetCUrsor(uint8_t x, uint8_t y)
{
  Serial.write(0x02);
  Serial.write(x + 16*y);  // 16 should be 20 if your screen is a 20x4  or a 20x2 
}
void LCDSetCUrsor(uint8_t x, uint8_t y)
{
  Serial.write(0x03);
  Serial.write(x);
  Serial.write(y);
}

It doesn't work properly. It only erase the first two letters (with LCDSetCUrsor(0,3);). I have Arduino Due, could it be the problem?

the code sets the cursor on a certain position. It does not clear the screen. check the PDF

12 Clear screen Clears the screen and sets cursor to the home position

void LCDClear()
{
  Serial.write(0x0C);  // 12 decimal
}

Thank you! Now it works perfectly!