You best instructions should come with a couple examples. If you can have someone or yourself make a couple floats to display during the workshop that would be best. Above is my personal float that I used in the instructions and on display. It is made out of a shoebox, cardboard, paper, double sided tape, tissue paper, glue and string. If you provide the shoe boxes and string, that is helpful too.
Anyway, I always show people how easy it is to find images or patters on the Internet or on your computer so that it makes designing your float that much easier. It is also a good idea to sketch it our first so you don't get confused or forget anything.
Floats can have ANYTHING on them - or you can make it fun and have theme to your parades, like most major parades do.
Here I had a display board with things like "Patterns", "Textures", and "Designs"...I found this pattern on the computer and just simply added colored tissue paper to make it really 3D and look much more like an actual float.
Here I show that I added a "skirt" to my float to cover up the shoe box. I had added felt to the top of my float to look like grass too. Kids and adults alike have fun getting really creative with their floats adding action figures, dolls, stuffed animals, or tiny cut out of themselves to floats.
Get creative and have fun!