Dia de Muertos is celebrated from November 1st to the 2nd. To remember your loved ones, ofrendas are made, fro those who journey from the land of the dead. On the ofrendas you put their favorite things like food, objects, drinks, etc.
Ofrendas can be many sizes, there are really huge ones that are beautiful, and there are also beautiful one-layered ones. There are seven leveled ones that represent, in Aztec culture, the seven layers represent the seven destinations. Many alters have seven levels but they can also have three or two. When an altar has two levels it represents the earth and the sky. The significance of three levels is heaven, earth, and the underworld. For the different levels you can use different sized boxes and cover them with table cloths or zarapes.
To make your ofrenda, you will need:
Cempasuchil:
Marigolds not only make a pretty scene and smell good, but they attract the souls of the dead. You can make a trail-like line down the middle of your altar to help guide them.
Pan de Muerto:
Pan de Muerto is a type of pan dulce that is made especially for these times. The bread has a design at the top of a criss cross shape that represents bones. The breads can have sugar on top or sesame seeds or just butter, and some may come with filling.
Candles:
The candles on the altar represent hope and faith. The light is another way for the souls to guide themselves to your altar. Many times, people put the candles in the form of a cross.
Papel Picado:
These thin colorful sheets with cut-outs symbolize the union between life and death. It also is associated with wind because when a soul has arrived the paper will move.
Drinks and Food:
For everyone the food on the altar will be different because you put the food that your loved ones enjoyed.
Sugar Skulls:
The sugar skulls symbolize the sweetness of life.
Personal Objects:
Scattered on the ofrenda, you would put personal objects that were meaningful to whomever it was that passed. Many people for kids will put toys and for adults clothing pieces they may have worn fairly often, or something as simple as a needle and a thread if they like sewing.
Hopefully this gave you a better understanding of what you will need to have to make an ofrenda.