Multiple blinking LEDs

If your bicolor is a 2 pin, you need to drive it with 2 output pins, lets say 8 and 9, connect one end of the LED to pin 8, other end to current limit resistor (330 Ohm) other end of resistor to pin 9, then:

digitalWrite(8,HIGH); // RED ON
digitalWrite(9,LOW);  //     "

digitalWrite(8,LOW);  // GREEN ON
digitalWrite(9,HIGH); //      "

digitalWrite(8,LOW); // OFF
digitalWrite(9,LOW); //     "