Summarize the following:
On the homepage, you'll see a box that says "Design Custom Maps" with more information about designing a custom map. You'll also see a button that says "Start Now." Click on that button. Sign up before beginning, so that you can keep your map. If you can't see your country, zoom in first. Then click on the country to bring it to the fore and use the zoom in and out buttons to get the portion of the map you wish to have. Choose a color (this can be anything, including "Cucumber" and "Sherbert.") The color will fill out the background behind the map. You will have an option to continue customizing this color in the next section. Then choose a street or terrain as your starting point. You can also choose satellite as the base layer if on a paid account with MapBox.com.
Head to the MapBox website at http://www.mapbox.com. Choose a starting point in designing your map.