For this achievement, you need to complete a single chapter without missing an attack skill. Attack skills are the red skills (Bullet of Fire, Splashdown, Psycho Spear, etc.) You will likely get this achievement naturally on one of the earlier missions.
However, if you are having trouble with this achievement like I did, you will unlock it automatically after beating the Chapter 2 mission 'Continue: Erase Skills' as there are no attack skills for you to use.