The example maps are a collection of maps that come with a fresh copy of Essentials.
As the name suggests, the example maps contain examples of many different features available in Essentials.
The example maps are joined together to form a small "region" (and thus provide an example of that too, along with map connections and various ways of moving between maps). Examples of similar features are usually grouped on the same map/maps, and are usually in logical places.
They are very useful when wanting to find out how to do something relatively simple (for a Pokémon game).
When you start making your game, probably the first thing you will do is delete (at least most of) the example maps and start making your own. See below for what would be involved in this.
Map 001 is the Intro map. This is the map which should contain the player's starting position, as the player is put there immediately after choosing to start a new game.
The map is entirely blank, and contains a single Autorun event in the top left corner which plays the Professor's lecture (including name/gender selection). The version of the lecture that comes with Essentials is based on the FireRed/LeafGreen one, and is rather robust.
At the end of the lecture, the player is transferred to the place where they actually start the game.
There is a second event on this map, in the bottom left corner, which exists only for debugging purposes. It is used to skip the lecture, automatically assign the player a pre-determined gender and name (male and "Red", respectively), and quickly start the game proper. By default, it is set to trigger via Action Button (which means it cannot be run during a proper game because there's no way it could be interacted with). To use this rather than the lecture, set this event to Autorun and the lecture event to Action Button - remember to change it back once you're finished!