Rather than beginning with large models, start with kits with large parts. Most snap-together kits have few small parts, and they are a natural place to start. Several brands are available, usually in hobby shops. Enamels are oil-based paints and they require paint thinner to thin and clean up. Enamels are easy to apply and come in a wide assortment of colors.
Enamels also are available in spray cans, many matching bottled paints in the same line.
Water-based acrylic hobby paints are becoming more popular. They are more difficult to airbrush, but they are less toxic than enamels. Most acrylics are thinned and clean up with water. Some modelers prefer to work in one scale only so they can see the size relationship of their subjects. But others may not be concerned with constant scale.