ClipClapCat said: Sorry but how do I know what direction the window is facing?
The important thing is how much sunlight comes through a window. In the morning when the sun comes up in the east, the east facing window will receive the most light, but by near noon that light will be more overhead and not coming through the window. As the sun moves to the west horizon, in many parts of the northern hemisphere it's slants in from the south. That is why a window with southern exposure tends to get the most light. As the sun traverses from sunrise to sunset, that slant causes a lot of light to come in directly, giving the most light to windows with southern exposure. However, depending on your case and where your windows are located and what might block the sun from coming in, just observe which windown have the most bright light coming in throughout the day. That will be the best window to locate a light-loving plant directly in front so it can receive the most light. Blinds, shades, curtains etc. should be open.
