[Japo]

In the inventory window you can click on the tabs at the top ("all", "weapon", "apparel", "magic", "misc") to filter the items you see.

You can see the map when you right-click, along with the inventory, magic, and stats. You can toggle between a local map and a map of the whole island by clicking on the button. It will show points of interests after you've explored them or told about them, but until that you can learn about new places by reading some books or papers (for example, the "Guide to Vvanderfell"). A great way to learn about new places is to accept quests (after joining the guilds for example), most will require you to travel. But the island is huge, you can finish the game without seeing lots of it.

The main purpose of the "food" is as alchemical ingredients. To perform alchemy you need at least a "mortar and pestle". When you hover the mouse over an ingredient it tells you what effect it has. You can perform alchemy by dragging the mortar and pestle over your character's image in the inventory window. Then you make potions by combining ingredients: a potion has any effects (positive or negative) that at least two of its ingredients have in common.

Eating ingredients alone without preparing them into potions has no effect. If you aren't going to do alchemy for now, it's best to just sell all that.