Calling a Simulink-generated DLL from another DLL

I have some Simulink-generated DLLs which I need to exploit on an external application via another DLL to perform dynamic simulation.

I need to code the C++ script in the main DLL which calls for the functions of the simulink DLL. These functions allow ideally to initialize the DLL (which represents a simulink controller model) and evaluate its output. This code is later compiled in the main DLL, which is used by the external application which calls for its functions whenever a new evaluation of the model is needed. The issue is that I have no idea how to write the C++ code to exploit the simulink DLL.

I can find tons of help about how to generated the DLL from a simulink model, but I can't find any help or examples regarding how the simulink DLL is exploited by an external application. The only links I found on old threads are no longer online.

Can someone redirect me to help on this topic?

Thank you in advance, Regards