You will need:
-length of 1/16 in (or other) the width of the window to where you want the curtains to stop plus about 4-5 inches
-eyelet screws, 3 per window
-cable crimps or ends
-needle nose plyers
-some curtains to hang
-tape measure helps.
Step 1: Measure the window you will be covering.
Add about 4 inches to this number for the loops at the end.
You will want to only loop and crimp one end of the cable to start. We will check the final length before looping and crimping (swaging) the other end, this will ensure we get the cable pretty taught and without too much sag.
Here my window is just over 39 inches, I cut 45 inches of cable to be safe.
Step 2: Install eyelets above window.
I used the molding as it was more secure than the drywall, make sure you use a strong enough eyelet and anchor it well enough to support the weight of the curtains and the force of opening and closing them.
I used closed eyelet screws that I opened just a bit with needle nose pliers to fit the cable. This way I can re-close them after I hang the curtains and know the cable wont come off or fall down.
Place one eyelet on each side of the window, and one in the middle for support.