You can use macros to modify the way that the project system refers to files.  Macros are divided into four classes:

System Macros
These are provided by the Studio application and are used to relay information from the environment, such as paths to common directories.
Global Macros
These macros are saved in the environment and are shared across all solutions and projects. Typically, you would set up paths to library or external items here.
Project Macros
These macros are saved in the project file as project properties and can define macro values specific to the solution/project they are defined in.
Build Macros
These macros are generated by the project system whenever a build occurs.
System macros

The following macro values are defined by the system

Macro Description
StudioDir The install directory of the CrossStudio application.

System macros can be used in build properties and also for environment settings.

Global macros

To define a global macro

Project macros

To define a project macro

Alternatively you can set the project macros from the properties window:

Build macros

The following macro values are defined by the project system for a build of a given project node.

Macro Description
ProjectDir The project directory.
ProjectName The project name.
Configuration The selected build configuration.
SolutionDir The directory containing the solution file.
SolutionName The solution name.
InputFileName The name of an input file relative to its project directory.
InputName The name of an input file relative to its project directory without its extension.
InputExt The extension of an input file.
IntDir The macro-expanded value of the Intermediate Directory property.
OutDir The macro-expanded value of the Output Directory property.
EXE The default file extension for an executable file including the dot.
LIB The default file extension for a library file including the dot.
OBJ The default file extension for an object file including the dot.
LibExt A platform specific library extension that is generated based on project property values.
Using macros

You can use a macro in a project property or an environment setting using the $(macro) syntax. For example the Object File Name property has a default value of $(IntDir)/$(InputName)$(OBJ).

To enable debugging of builds you should use the Build Information... dialog that is on the context menu of the project explorer. This dialog will give a full list of the macros that are specified for the project node selected together with the macro expanded property values.