This is the short version... if you need more detailed instructions, post your question in this thread.
We need to turn each layer into a pattern then you can use them whenever you paint and never have to open the engine turned layers again.
Open the engine turned layers, turn off the read me layer (click the little eyeball in the layers pallet), select the next layer down by clicking it, click the edit menu up at the top of the screen and down towards the bottom it says 'define new pattern', click it and it should save the pattern.
Now turn off that layer and click the next color layer and do that one the same way for all 25 layers if you want them.
Now go to your car template, create a number or shape or whatever, and use the Layer Effects (just double click the layer in the layer pallet to get the effects box to pop up) like you were going to add an outer stroke to the number.
Select Pattern Overlay and in the dropdown box there select the pattern that you just made. Play with the scale slider to get the size you want. I find that 25% 50% 75% and 100% look the best.
You can use them the same for shapes, or as the stroke of a number, just click stroke in the Layer Effects and in the drop down box there select pattern as the fill and choose the pattern.
PSD Version here:
http://www.racingrafix.com/forum/index.php?action=media;sa=item;in=17823PSP Version here:
http://www.racingrafix.com/forum/index.php?action=media;sa=item;in=17824