You should figure out how much space you are given and the various rules or regulations the carnival has regarding the size or shape of your booth. Once you understand these regulations you will be able to start constructing your carnival booth.
Go with ready-made options:
If you have a little bit of extra cash to spend then you should look into ready-made options that are basically just a canvas canopy on an aluminium frame. You can find these at any decent outdoors or camping supply shop. Using a ready-made canopy can really save you a lot of time and energy which you can use to decorate your booth instead of constructing.
Get folding table / chairs:
There is a good variety of simple folding tables and chairs that are available in the market at an extremely low cost. Buy one or two folding tables and a couple of chairs that you will use to sit on behind the front of your carnival booth. These items are usually lightweight and are made of plastic. Depending on the theme of your carnival booth, you can buy a variety of different plastic racks to hold merchandise.
Get some help:
Try to get a friend or family member to help you construct your carnival booth. Always remember to tie down the canopy legs to the ground so that it does not move or collapse from a sudden gust of wind or someone bumping into the booth. Once you have put up the canopy, place the folding tables in front and the chairs and plastic racks in the back.
Take some colourful drop cloth and drape it over the sides of the canopy. Be sure to secure the cloth so that it does not fall down. Also, drape colourful cloth over the tables so that it is close to touching the ground. This will give the effect of being a wall for your carnival booth. Take a big piece of cardboard and colourful paints to write the name of your carnival booth. Remember to secure it to the top of the canopy so that everyone can see it.