You may open a map property dialog by double clicking a map's name in the resource list.

And then you will get a dialog like this:

Let's see the details about the fields in the dialog.

1. Map Name
Name of the map.

2. Background Image
Background image of the map. Normally a map must have a background image.

3. Map Type
In current version, OGE/OGM supports 3 map types: Scrolling, Tiles and Isometric.

4. Tile Width and Tile Height
You must fill these two fields if you want to create a Tiles/Isometric game map.

5. Tile Origin X and Tile Origin Y
OGE/OGM will use these two fields to align the sprite in a tile.

6. Row Count and Column Count
These two fields can define the size of the tile table.

7. Position of the first tile
In an Isometric game, OGE/OGM need this information to translate the coordinates between tiles and pixels.

8. Tile Value
After you open the "Show Tile Value" option, you may set the tile value by left clicking (increase) or right clicking (decrease) the tiles in the map.