Open the Texture Application (Shift+A), select a face, or just a texture from the list, fill in the properties that you want to change and right-click on the face you want to apply this texture and these properties to.
Leave properties blank when you don't want to change these. For example, a surface has texture 'BABTECH_DR1E'. You left-click on it and it's properties will then be displayed in the Texture Apllication. You can then change properties: scale, alignment, rotation and texture. Then you right-click on this surface to apply them. When you right-click on another surface, you apply this texture and these properties to that surface as well.
In case you've scaled several surfaces textures up, and want to apply another texture to them but not change their scales, you would leave the scales propertie empty.
Aligning textures to world means it's getting aligned to the grid. Aligning them to face will, well, align them to that face. This means it wont get stretched when the surface is steep, while this would happen when it's aligned to the world.