Looking at games you might play regularly, you're probably wondering how you'll ever create models and objects that look so realistic you could reach through the screen and grab them. Fortunately, Unity has a set of primitive GameObjects that you can select from to prototype faster. These won't be super fancy or high-definition, but they are a lifesaver when you're learning the ropes or don't have a 3D artist on your development team.
If you go into the Hierarchy panel and click on Create | 3D Object, you'll see all the available options, but only about half of these are primitives or common shapes:
Other 3D object options, such as Terrains, Wind Zones, and Trees, are a bit too advanced for what we need, but feel free to experiment with them if you're interested. Before we jump too far ahead, the arena needs a floor, so let's create one.