Light Chanuka candles from left to right, as you face it, not as it will be seen from outside the window. Add the new candle from right to left.  For example, on the first night, put the candle on the extreme right of the menora.
To set up and light Chanuka candles:

• Set up the candles starting from the right side of the menora.
• Light the shamash candle and hold it while you say the blessings:
  • Lehadlik ner shel Chanuka.
  • She'asa nisim l'avoteinu ba'yamim ha'heim ba'zman ha'zeh.
  • (And on the first night, add) She'hecheyanu.
• Light the left-most candle first and proceed to the next candle on the right, and so on.
• Once you have lit the first candle each night, say ha'neirot hallalu (this is a halacha).

Note Once the menora has been lit, you may not turn or move it, even to the window.