This beanie was designed in 2 sizes.

Woman’s (20”-22” circumference and 7” to 7 ½” drop)
Men’s (23”-24” circumference and 9” drop)

You will also need size 10 (6mm) & 10 1/2 (6.5mm) circular needles
and a set of size 10 (6mm) & 10 1/2 (6.5mm) double pointed needles.

I would consider this pattern easy.