Double check all your steps first. Have you done everything correct up to the last paragraph? Are you sure? Are you REALLY- sure? Excellent. Lets carry on.
Mapping textures comes AFTER you finish applying all the textures to your mesh as you want to. In order to map textures on a mesh, you need to first open the unwrap UVW modifier from the modifier list on the right hand menu. Scroll down in the dropdown list till you see the option, then select it as shown below:
REMEMBER TO EXIT POLYGON MODE OR ANY OTHER MODE BY RE-SELECTING THE APROPRIATE ICON BEFORE YOU OPEN THE MODIFIER OR TEXTURING WILL NOT WORK AS REQUIRED.
Notice when you open the unwrap UVW modifier, you can see the textures applied to the mesh, but they seem to be stretched/distorted etc? This is because the textures are only APPLIED, not MAPPED. We need to do the mapping for each face, and this is what the UVW modifier allows us to do.
Once youre in face mode, begin to select the first face(s) you wish to work on/map textures for. I decide that i want to map the green textures surrounding the windows [i classed them as trims for the sake of explaining, but theyre obviously not, you need to assign proper trimming textures]
Hitting the quick planar map button after selecting your faces and selecting the averaged normals option will automatically map the texture for you without any distortions/stretched faces etc, HOWEVER, it does not necessarily mean it mapped it in the correct rotation as you want it, or the size you want it to ideally be. It only maps the faces to the size it should be, nothing more, nothing else, but is an extremely useful tool nonetheless. Youll use it often. Sometimes the texture may not map properly with the averaged normals option, just experiment with the x, y or z axes then till it works.
To ensure that the texture rotation is to the standard you want, and is the size you want, you need to hit the edit button, which opens a new window displaying the texture, and the faces selected on it.
The triangle button next to the dropdown, when selected, will only display the selected faces from the viewport in the window. Very useful if the window gets rather cluttered/messy (which it may at a later stage). The 4 buttons at the top left corner of the window are for moving, rotating, scaling, and freeform mode. Youll mostly be working in freeform mode, but you may from time to time need to use the other modes as well. For example, in this situation, i need to rotate the selected faces map co ords, so i select the rotate icon, and rotate the faces by clicking, holding and dragging around in a circle till i have the faces lying in a desirable direction. In freeform mode, i select one of the corners, hold down control, and drag the corner outward to increase the size. Holding down control means the size increase will remain in the same shape as before, no distortions.
As you can see, the selected faces now have correctly mapped textures, which means youre ready to move onto the rest of the models. From here on its basically a repetition of this step again and again until youve mapped the textures on every face of the mesh.