The purpose of having an altar in your home can be as simple as reminding you to take time for serenity each day.
At its most essential, an altar is simply a raised structure that serves as a resting place for meaningful objects. It focuses the eye and provides a place for contemplation and, if so desired, ritual. All of these elements can be quite simple. One idea for a simple altar is a pot with a bulb planted in it, set on a box. This altar to growth can act as a reminder to you that all living things bloom in their time. A simple ritual might be to write down dreams you would like to see come to fruition on scraps of paper. You might place these scraps of paper in the box, or under the flowerpot, or in an envelope you prop against the pot. As the flower grows, so will your dreams.
If you look around your home, you may find that you have already created altarlike arrangements without even really thinking about it; this is something we humans do quite naturally. A candle, a decorative box, and a vase of flowers are just a few of the common household objects that lend themselves naturally to the creation of an altar. Simply add intention and intuition, and you have created your first altar. Remember that it isn't necessarily about the objects you place at your altar--it is the time you spend with it daily, taking the time to be with it for your sacred time.