How does matrix multiplication work in the System.Numerics. library?

Question

C++ / C#

I read the documentation and a couple more articles, but I didn’t find a normal video tutorial. Give an example code for matrix multiplication. And in general, what does the matrix look like in this library.

Answer 1

You can see the code for a 4x4 matrix for yourself, for example:
https://github.com/microsoft/referencesource/blob/...

Answer 2

for use here https://numerics.mathdotnet.com/Matrix.html
and sorts can be viewed on githab, as already suggested by Nikolay