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The process of using CMake to incorporate C++20 modules can be broken down into the following steps:

1. Update the CMake version to at least version 3.20. This is required as CMake 3.20 introduced support for building C++20 modules.

2. In the CMakeLists.txt file, set the C++ standard to C++20 by adding the following line:

set(CMAKE_CXX_STANDARD 20)

1. Modify the target in the CMakeLists.txt file to use modules. This can be done by adding the following lines:

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fmodules-ts")

target_compile_options(<target_name> PRIVATE "-fimplicit-modules" "-fimplicit-module-maps") 

1. Add the module definition files (.cppm extension) to the project. These files describe the interface of the module and contain the implementation of the module.

2. Add the module dependencies to the CMakeLists.txt file. This is done by using the module command. For example:

module(foo_module foo.cppm)

target_link_libraries(<target_name> PRIVATE foo_module) 

1. Compile the project using CMake. The generated build system should now support C++20 modules.

Note that the above steps are only a basic outline of the process. The specific implementation details and requirements may vary depending on the project and the specific modules being used.