There are numerous ways to do this. Most of the ARFs' have one solid color as a base with other colors laid over the base. There is an art to this to prevent the trapping of air between layers, causing air bubbles. Many of the manufacturers do not have the time to do it right, so you get a lot of bubbles.

Another method is to prepare the covering in the appropriate sizes and lay it up on a flat surface prior to application on the airframe. Again, it requires a little talent and understanding of the covering material to be used.

To use the base layer method and applying the additional layers over the base requires that the base layer be completely applied and fully shrunk before application of additional layers. You can mix up a solution of about 1 teaspoon of dish soap to a quart or so of water. Brush the solution over the base layer and position the next layer where you want it. Use a very soft type of squeegee (I use a cut off piece of a new windshield wiper) and carefully squeeze out as much of the solution as you can. Once that is done, wait for a day or so to let any additional moisture weep out before you apply any heat.

Set your iron to a fairly low heat setting and slowly go over the top layer. Start at one end, and moving a very small amount at a time, activate the adhesive on the top layer. The heat setting will be trial and error until you find the heat that will activate the adhesive without causing bubbles. Once that is done, go to a high heat setting and iron down all the edges, and only the edges, of the application.

Be sure to use a "sock" or some other material, over the face of your covering iron to prevent scratching the covering. Don't use any material that has nylon, rayon, or some other plastic as part of the material composition.

If you are going to use both Monokote and Ultracote in a color scheme, be sure that the Monocote is the base layer. It reaches full shrink at a much higher tempeature than Ultracote. If you use Ultracote as a base layer and Monokote on top, you can easily burn a hole in the Ultracote trying to get the Monokote fully shrunk.

It's going to take time, trial and error, and practice, but once you figure it out, you will have a plane that has a finish no one else does.

For a lot more information on finishing, pick up a copy of
"There Are No Secrets" by Harry Higley at your local hobby shop. There's a lot to be learned, and his book gives you a pretty good boost in the learning curve.