What happens next?

How to make sheer curtains
Use measuring tape to measure window height from the point where the curtain rod will be to the bottom of the window.
Decide how much longer you want your curtains to be than the window.
Measure length of the curtain rod.
Measure circumference of the curtain rod and add 1 inch (2.5 cm) to allow for a seam. How full your curtains are is a matter of taste.