Here are all the steps:
git clone https://github.com/JuliaInterop/libcxxwrap-julia.git
cd .\libcxxwrap-julia\
mkdir build
cd .\build\
cmake -DJulia_EXECUTABLE="C:\Users\rrhie\AppData\Local\Programs\Julia-1.6.3\bin\julia" .. -G "Visual Studio 16"
cmake --build . --config=Release
ctest . -C Release
The last line tests if the library is build correctly and if CxxWrap can find libcxxwrap-julia
Test project C:/Users/rrhie/Documents/julia-projects/libcxxwrap-julia/build
Start 1: test_module
1/3 Test #1: test_module ...................... Passed 1.32 sec
Start 2: test_type_init
2/3 Test #2: test_type_init ................... Passed 1.31 sec
Start 3: test_cxxwrap
3/3 Test #3: test_cxxwrap ..................... Passed 39.59 sec
100% tests passed, 0 tests failed out of 3