Earth data contains the terrain height data. That will deterimine the style of the race. At this moment you can only download the data for Dakar 2012 (here), which is also good for 2013. Unfortunatelly the size of the data for the whole earth is to large, but i have if you need any part of it (from America to the Arabian peninsula).

Open earth data texture

Start the image manipulation program. Open image: <game path>/data/earthdata/earth_data_texture.png.

Steps inside the game

start the game
put the game into editor mode (left-bottom on the main screen)
save settings to make the editor mode permanent
click on Start New Game
if there was already at least one race, then click on Start Game on the stage screen
press F3 if you are in the game, that will open the editor window
click on RaM tab (Race Manager)
type race id: dakar2013
click on create (new directory will be created under data/races)
double click on the new race in the list (race window will be opened)
fill necessarry datas
click on Save (race.cfg will be created under data/races/dakar2013)
to create new day: type Day id: day01
click on new day (day01 directory will be created under data/race/dakar2013)
double click on the new day in the list (day window will be opened)
fill necessary datas
click on Save (day.cfg will be created under data/races/dakar2013/day01)
to create new stage: type Stage id: stage1
click on new stage (stage1 directory will be created under data/race/dakar2013/day01)
double click on the new stage in the list (stage window will be opened)
fill necessary datas
click on Save (stage.cfg will be created under data/races/dakar2013/day01/stage1)
click on activate race to make the stage active, so next time if you place an object it will be visible

Now you have a race with an empty stage. You will need to edit the stage. Close stage, day and race window.

Navigation

switch to the image manupulation program and select the pixel where you want to go: 1819, 2730
type these coordinates into tileX and tileY
click on reset (game will place you at that coordinate)
type F to switch free flight mode, where you can navigate with the cursor and mouse
you can increse the speed of the camera by O, decrease by L
you can see some status in the editor infobar at the top-left corner

Action

select a place where the stage should be
press F3 again to open editor window
select add AI point in the action list
click on action
you can now navigate again
click with the left mouse button to place an AI point (next time you select the stage, you will be place there)
press F4 to exit from the ACTION mode
double click on the stage line in the list (stage window will be opened)
click on save

Continue race creation

You can any time stop editing the stage and continue later. Be careful to save all data (roads, stages, days, race).

Add race picture

After restart the game, you can see a strange picture at the race picture. You can change it any time.

quit the game
find a suitable picture
copy it to the race directory, e.g.: data/races/dakar2013
you can edit the name of the picture later in the race editor window