1) Choose and set up terrains

First and foremost, you have to choose terrains and create them.
Three terrain types exist : walk, death and slide. It's useless to explain their role, their names are enough. You have to choose at least one walk, one death and one slide (unless your escape is just a maze, then you only need walk and death).
On the ground, you normally can see two terrain types, one for checkpoint, which will be walk, and the whole rest of the map, which will be death. You have to give a name to those terrains and identify them as walk and death.
To create the walk terrain, you have to use command "-newWalk" (-neww) with as parameters a label (name of your choice) and a terrain type of Warcraft III. To know which terrain type is under your feet, use command "-getTerrainInfo" (-gti) and do a right clic on the ground. A description of the terrain clicked displays. Note down the number after the terrain name. It is the id of the terrain. Type "-stop" (-s) to be able to move again. So, to create the terrain walk, type command "-newWalk walk ‹theNumber›" (without ‹ › of course).
Repeat the same task to create death terrain, but using command "-newDeath" (-newd). You will notice them that the terrain supposed to kill, kills now.
For slide terrain it's a little more complicated because it's not already present on the map. You have to start by choosing a terrain type, getting help with command getTerrainInfo, this time giving it parameters. For example "-getTerrainInfo 1 15" displays the 15 first terrain types, knowing there are 177. If you want the usual ice, its ascii id is 'Nice'. So type command "-newSlide slide 'Nice'".
Create some ice to check the terrain has successfully been saved. For that type command "-createTerrain slide" (-crt slide) and do two clicks on the ground, forming an ice rectangle. Use then command "-s" to be able to move, and check it glides well ;).
Command "-displayTerrains" (-dt) gives you a summary of the terrains you have added, with their characteristics. For example you can see that your slide terrain has its speed property set to 550. To change this property type command "-setTerrainSlideSpeed slide ‹newSpeed›" (-settss).
To create some walk, death or slide you will need to type commands "-crt walk", "-crt death" and "-crt slide".
You obviously can change at every moment the terrain type of a terrain, its appearance will instantly be modified on the map, this changing nothing to the gameplay. For this use the command "-changeTerrain" (-cht), for example type "-cht slide 'Nsnw'" to change ice to snow.
You can erase a terrain with command "-removeTerrain" (-remt) too. This command is only for administrator. Ex : "-remt slide". It doesn't delete the terrain on the map, but its properties (slide won't glide anymore, death won't kill anymore).
You can give an alias (second name shorter) to a terrain with command "-setTerrainAlias ‹terrainLabel› ‹alias›" (-setta). Terrain labels and alias are both usable for every command.