Wheels are circular, low-level effects. Wheels comes with a nail that is placed in the center of the item and then nailed into a post, broom handle, or anything solid that can be planted into the ground.
You just want to make sure you are giving yourself a few feet all around for the items to be safely used. Once lit, a wheel will spin in a circle and create a shower of sparks. Wheels are a beautiful effect and a ton of fun!