Like in many other great RPGs, the world map serves as one gigantic location where you can access every other location in the game. Here, you can traverse the world on foot, although you're restricted to plains, forests and other similarly flat landscapes.
As you travel, you'll occasionally be beset by the local wildlife (or imperial invaders) in the form of the infamous random battles . When this happens, you'll switch over to battle mode, where you must defeat all the on-screen enemies to progress (or you could try to run away).
Located at various points on the world map are many landmarks that you can visit, such as towns and dungeons. These places appear as an orange circle on the bottom screen world map and it's usually very obvious if you can visit them or not.
Additionally, so you don't get lost, your next destination is always highlighted by an orange exclamation mark on the bottom screen. Meanwhile sidequests appear as blue exclamation marks . So long as you use the map well, it should be easy to get where you want, unlike a certain Pope...
Whenever you're on the map--whether it's the world map, a town or dungeon--you can access the handy Map Menu by tapping the left-most icon on the bottom screen or pressing Right on the D-Pad. We'll mention it here since there are more options available on the world map.
In particular, you can access the Save menu at any time by selecting the feather pen icon at the very top. If you access it on the world map, the Save and Update Data options will be available--whereas they'll be greyed out if you're in a town or dungeon.
Passage of Time
As you dawdle on the world map, the time of day will eventually change from day to night and back to day. Besides the obvious visual (and audial) change between day and night, the enemies you encounter may change depending on the time of day.
For example, when it's night time, undead-type monsters will be on the prowl, while certain day-time monsters will be absent because they're asleep. By the way, the day and night cycle also affects town and cities--inns and shops will still be open at night, but the atmosphere is very different.