Take the zip folder, chuck it into your Dethkarz\Data folder, extract it and will give you a save file with each different vehicle that has access to every Cup

If using Steam, right-click -> properties -> browse local files, from there click the "Data" folder and put the zip in that and extract

If you just want a specific save with a certain vehicle, the following saves contain each one

savegame0 = Hyperon savegame1 = Astor savegame2 = Anassi savegame3 = Blitzwagen