save the image in black/white to a flash drive. Take it to kinkos and have them print it on something heavy. (cardstock, or plastic) make one copy for each color in the pic.
now cut the logos out, leaving an identical tab at the top/bottom of the stencils. this will help you line them up.
The first one will be your white inner cirlce.
The second will be your Steelers lettering.
The 3rd will be your yellow diamond
The 4th will be your blue diamond
The 5th will be your red diamond
You could combine the three diamonds onto one stencil, if you wished. as long as you remember to do each color separately.
The last one will be the outer grey/black ring.
Lay down your white, let dry.
Do your stenciled letters second. You may need a level to make sure that they are nice and even. Let dry
Do the diamonds. Since this design is rather simple, you will probably do alright with 1 stencil. Make sure that you are pressing on the stencil, and that you do not use too much paint, or else the paint will bleed under the stencil edges. Also try to swipe your brush from the outside of the stencil. Driving the brush towards the edge will make them look rough and uneven. Let Dry. I'd let each color dry, before working on the next.
Do your final outer ring, if you wish to, in whatever color you like. just remember, you can add more dark color onto light paint; but it is more difficult to lay white paint on top of dark colors.
You may need to go back and do some steady handed touch-up.