While you may search at any of these levels, high-level searching can overwhelm you with too many results. It's better to use all six digits if you can. A record may carry several codes to describe different aspects of the design or multiple ways of looking at it. A shaggy dog in a circle might incorporate design codes for both dogs and circles, while Raggedy Ann and Andy are coded as groups of children, boys, girls, stylized children, and dolls. Even with multiple codes, it's not always a simple matter to search for designs.
Funny shapes can be particularly nightmarish.
Sometimes selecting codes is a process of elimination rather than a positive choice. Perusing the code manual may reveal that you need to look in more than one place, or an unexpected one. Similar objects may appear in different classifications such as frying pans in Household Utensils, but electric frying pans in Lighting, Cooking, Heating, Cooling, or Refrigeration Equipment. Search for a word in the mark or for an element of the image. Search for an element of an image, in words.