How do you get chapter 2?

Simple, Complete Chapter 1, and Chapter 2 will appear.

If you're asking how to beat Chapter 2, then here's how:

Equip 3 Scrolls from the list to everyone:

Null Numbing Lv. 1
Null Paralysis Lv. 2
Book of Attacks Lv. 1
Book of Attacks Lv. 0
Book of Attacks Lv. 2
Book of Health Lv. 1
Book of Health Lv. 2
Book of Chakra Lv. 1
Book of Chakra Lv. 2

Numbing happens in this Chapter. Which is where Null Numbing comes in handy.
The Enemies here are easy to kill. Simply beat them to open Lightning Walls, then you have to Battle Tenro Chunin. He's a little more challenging than the first Boss, because he can attack from underground. But you can damage him anywhere. Also try attacking from behind so you won't receive any of his attacks.

I don't know if this is the Answer you were looking for, but I Hope it helps!

After you completed all the tasks in chapter 1 (4 tasks-don't care what grade you got just as long you have completed it) exit the game and go back into your game like this :

Press "start" -> "Scenario Mission" -> "Chapter 1" (press any button except "X" button until there are 4 small boxes with characters appear on right-top beside mission select..click "O" button to get into the real story mode Chapter 1 (not "Drill")..good luck !!!