A decal is like the spraypaint the players place. The difference is that we as mappers may set those when we create the map.
We mostly wanna do this to info the player about something. That would be anything from bomb target, name of bombspot to hostage rescue area.
What we need
We will need some decals to add. I expect you know how to add a wad. You should add the decals.wad to make decals. When the decals wad is added you are ready to proceed.
We found something to blow
This is indeed an ugly house, so we are gonna blow that away. We need a bombspot so the terrorist can see this is the place to bomb.
Selecting the decal
The decal we will use is called {target. We find it among the normal textures. Typing { in the filter will make it faster to find the decals.
Placing the decal
First we move our camera view to the spot where we wanna add the decal.
Then we choose the apply decals tool (shift + D).
The mouse pointer will now look kind of splashy. Now click once in the center of where you whant your decal in the camera view. This can be triggy ;). If it doesn't work you might have marked the camera Icon along with the apply decals tool, in that case unmark the camera and try again.
As soon it looks something simular to this you deselect the apply decals tool and you are done.
Conclusion
Ofcourse we would also need some entities to make the bombspot actually work but that has ben covered in the how to make de_maps article
