Unlock the window by pulling the locks on top of the bottom half out toward you.
Locate the plastic clips on the top sides of the window. Pull those down until they snap into the bottom half.
Pull the bottom half of the window toward you. Rest it on a high surface such as a stool or chair so it doesn't swing down and hit the wall.
Push the plastic clips back up to the top of the window. Pull the top window down about 6 inches.
Find the two plastic clips on the very top of the window panel; there is one located one each side. Push those in toward the center and pull the window toward you. Lay the window down on top of the bottom window.
Spray the outside of the top window with glass cleaner and wipe it down with a lint-free rag. Spray the inside of the tracks (located in the wall) with a silicone lubricating spray and wipe them with a different rag.
Close the top half of the window back into the frame. Push it up into the top half of the opening. Pop out the grids by pulling gently (not all windows have grids). Spray the inside of the window with glass cleaner and wipe it down with the rag. Snap the grid back into place.
Clean the outside of the bottom window with the glass cleaner and rag. Close it up back into the frame. Pull down the window slightly to release the locking mechanism.
Remove the grid (if you have one) by popping it gently out of place. Clean the glass with the cleaner and rag. Snap the grid back into place.
Push the window down into closed position and turn the locks back to the locked position.