when i create my terrain its so little that i cant even see it. how do i make it to look like the ones in the tutorials?

First, you double click the terrain in the hierarchy so you zoom in on it. If this does not fit your needs, go to the inspector, go to Terrain(Script) and click the gear. Then set the terrain resolution higher. This will make it considerably larger, but the default terrain is already pretty large for me. (My opinion)