1) Open your coat of arms document in photoshop.

2) Flatten Image. When working with the pen tool and various other tools, a new layer is created. It makes it impossible to edit the shape so we will need to Flatten our Image often.
>Layers
>Flatten Image

2) Select a color. Double click on the foreground color. A color window appears. Select the color. Press OK.

3) Select the pen tool.

4) Create first red quarter.
Put the pen over the corner indicated in the screenshot below.

Click once with the mouse.
Next, click on the center of the shield (two).
Next, click on the top corner (three).
Next, click on the next corner (four).
Lastly, click on the final corner (five) and DRAG to create the curve.

Here is what we now have.

5) Create second red quarter.
Using similar techniques, create the second red quarter selecting corner in the order indicated below.

6) Finally, choose a second color and color in the remaining quarters.

Flatten image.
7) Outline the shield (create a stroke).
Select an outline color of your choosing from the color picker.
Select the magic wand tool.

With your finger on the shift key, select each quarter.
>Edit
>Stoke
Choose 10 pixels.
>Select
>Deselect