How do you paint lines on the terrain?

Hello!
Recently I've been modifying some hills in the Utah map making Hill Climbing Tracks. Until now I've created the layouts of the tracks and edited the terrain but I don't know how to paint the white lines that appear on the Crawler scenarios, so that my track layouts are clear and recognizable and everybody knows where to drive in them.
Does anybody know where to find these lines in the World Editor and how to paint them on the terrain?
Here is an image so you know what I am talking about.

 

Those lines are decal roads, aren't made with terrain painter. Go to decal roads tab, press Alt key and click at the ground to make a decal road. Then, in the inspector menu set the material to line_white or smth

 

Thanks a lot! I will try to do that when I have time

 

I have tried to do this now and I found the white line material in the World Editor and was able to make a decal road but now the problem is that I don't know how to make that just the outline of the decal road is painted and not the whole thing like it happened for me. I've looked through the inspection window and tried to change some properties but no luck.
This here is what happened to me:
Does anybody know how to just apply material in the outline of a road, like in the Crawler scenarios?

 

There's no white outline material, you can make 2 parallel white decal roads if you want to make a route with them.

 

oh ok so what I can do if I want to have those white thin lines on a terrain would be to create two parallel white decal roads like you said and making those really thin by changing the width of both of them, am I right?

 

Yes