Step 1 一 Get the complete window measurements

Properly measuring your windows prevents problems like tracks that won’t fit, shallow frames, or curtains that don’t fully cover the glass.
Windows are often surrounded by obstructions such as walls, beams, air conditioners, pipes, furniture, and curtain boxes. When deciding on curtain sizes, please ensure that the area to be covered by the curtains is completely flat and free of any bumps or protrusions.

What are the full dimensions of the mounting range inside/outside the frame?
How do I determine whether my curtains are suitable for installation inside or outside the frame?
>>Complete Tutorial