After you've got your character customization under control, it's time to venture out into a bright universe... that holds a dark secret. Hopping from planet to planet in your ship (called the Normandy) is simplified by a galaxy map that scales to a solar system map once you've selected a system that interests you. From there you get a detailed read-out of each planet before deciding whether or not you want to land there, and what you'll need to survive in that environment.
You also get a combat ATV to tool around in, and you can customize this thing as well. This vehicle will get you where you need to go, but the most exciting stuff is more about what you do when you get there.