Import external C++ libs

Godot Version

4.2.2

Question

Unfortunately, the Example of “Binding to external libraries” seems not clear enough.
I want to , say, import whole bunch of Matrix Lib in C++(3.4.0 · libeigen / eigen · GitLab)
in C++, i just download the Source code(zip) then place it in the project file then config the path(Im using VScode so modify .json file)
but how in godot?
Lets say from after downloading the Source code(zip) from (3.4.0 · libeigen / eigen · GitLab) and got the eigen-3.4.0 folder