Hello. Could you explain me about igniter. What is that? I did not find about that in my manual book . Can I test it before changing and how? Thank you a lot for helping. :)

Controls sparking; i.e. when the coil's magnetic field builds up and collapses. Here's what they look like:

http://www.partsamerica.com/ProductList.aspx?PartType=194&PTSet=A&SearchFor=Ignition%20Module%2FControl%20Unit

Autozone will test them for free.