If you are referring to the paint scheme then most of us use the templates to map out the damage. Then use masking fluid on the area and paint. You repeat this process over and over for each color and area of the helmet.
There are two techniques one is layering which is just what it sounds. You layer the paints one over the other. In this technique the silver would go on first since it is the base.
The other technique is topical where you add the specific damage to a specific area. In this technique the silver might go on last...........or in the middle.
There are many WIP threads where you can see these types of painting techniques used.
