In a sense, as soon as you decide to take part in the Rio Carnival, the festivities will have begun for you. Aside from practicing your song and marching during Samba nights, you will also have a chance to make a costume. As you may be aware, each costume is carefully designed and created over the course of several months before the actual parade.
Regardless of the Samba school that you join, the "Carnavalesco" or Carnival Designer will play a key role in choosing the materials that will be used to create each costume. From there, artisans and others within each team will decide how to use the materials to create the most flamboyant displays that still match the theme for the school. Regardless of whether a Ground or Float costume is being created, they will begin by drawing the patterns on paper. Once the design is worked out, they will cut cloth and other materials based on the paper pattern. Finally, once the main shape of the costume is completed, the artisans will spend hours attaching sequins, glitter, beads, feathers, and other intricate items that will transform each costume into a beautiful work of art.
Typically, there will be approximately 200 people marching around each float. Individuals wearing "Ground Costumes" all wear the exact same costume. However, each wing will still have its own unique costumes, which must still adhere to the school theme.
The most vibrant and daring costumes are reserved for people that will go in the Float. These are the costumes that the Rio Carnival is most noted for. Even though they are extremely beautiful, these costumes are also fairly expensive and difficult to make. Parading in the Float is also much more difficult, since the floats tend to shake as they move along the parade route. That said, if you want the most challenging role in the parade, the main floater (who sings the Samba song at the very top of the float) might be the role you are most interested in.