This process is common to every pattern of yaksok kyorugi of Taekwondo. It should be settled who is attacker and who is defender. In this photos, the right person is attacker and the left defender.

The attacker moves first. He shifts from Junbi to Apkubi Arae Makgi. Here, the attacker should follow the ways of Samjae. It means he should not draw back, but drop his hip down bending his knee.

And the attacker yells with his motion. It signs that he is ready for atttack. Then, the defender get ready for defence. It means he thinks how he will move. He then yells, which signs he is ready for defence.

Refer to "Understanding the attacker's motion".

Pattern 9 is the following.

The attacker shifts from Arae Makgi to Apkubi Eolgul jireugi with one step forward. Then the defender drops down and move his right foot to the right with Jebi poom Mok chigi. And move his right foot to the back of the attacker's front foot, and fell him down and punch.

Technically, you should know what part you should hit with your hand knife at the motion of the third photo in this page.