Mandalas can be displayed as beautiful pieces of art in your home for delight you visually. But, they serve a larger purpose. Location of a mandala is important. Place them in sacred spaces as a shield to keep negative energies from infiltrating the area, or anywhere where you sense an air of vulnerability. This could be in an entryway, a hallway, bedroom, even inside a closet or bathroom.
Mandalas can be made using a variety of different art mediums including paint, glass, fabric, macrame, sand paintings, computer graphics, and more. I imagine macaroni glued to a paper plate could be considered a mandala if that was your intent. Consider how a chef artfully prepares a nutritious and colorful menu. He serves the meal it to his patron on a dinner plate. That plate represents a "whole universe" filled with his culinary creation... a mandala to be blessed and consumed.
Creating your own mandala can be healing in of itself, it is truly an introspection process. Simply allow yourself to discover those creative juices within that have been waiting for an opportunity to ooze or splat out. Don't be a afraid, go inward and awaken your senses. If you are having difficulty getting started, begin my doodling a few circles or spirals onto a notepad. Later on you can move to a larger canvas.
Also see: The Power of Awareness: An Excerpt from The Mandala of Being