Download the trail editor files from the following link: http://host.imailds.com/download/4x4files/4x4ed.zip
Installation on web server
Create a directory somewhere on your web server to house the trail editor files.
Unpack the files into this directory.
Browse to the 4x4ed.html file.
Using manual upload
If you do not have access to a web server, simply unpack the editor files to a suitable location on your computer, and load the file '4x4ed.html' into your browser. You will need to use the 'Manual' button for save and load operations, and follow the instructions provided in the editor to get the level files into your game.
Levels must be named 'levelXX.xml' where XX is in the range 01 to 18 and copied to a folder named /Android/data/com.imailds.android.adventures4x4/levels/custom/ in the external storage location of your device.
The game checks for these files at startup, so the first time they are created you must restart the game. After this, you can simply overwrite level files with new ones and select them from the custom level selection screeen.