In this tutorial we will create a realistic-looking curtain with the help of the Cloth modifier and Reactor. Let's start by adjusting the units. Go to Customize > Units Setup > Display Unit Scale set to Metric and Centimeters.
In the Front Viewport create a plane with these Parameters: Length=200; Width=60; Length Segs=10; Width Segs=21.
In the Left Viewport Create a Cylinder, just above the plane (Radius=1; Height=80; Height Segs=1; Cap Segs=1) and move the cylinder to align with the curtain in the Front Viewport.