Using an external library gives DllNotFoundException

Hi,

I'm trying to use https://github.com/entrepreneur-interet-general/H3.Standard with Unity. I've added the package with NuGet, but when I'm trying to use the methods, I get a DllNotFoundException about h3lib.dll. The InstanciateNativeLibrary() method given in the H3Standard puts the h3lib.dll to the project root, and not inside the Assets folder. If I add the .dll manually, and try to add the reference in Visual Studio, I get "File 'h3lib.dll' is not a valid .Net Assembly". Any tips on how I could get t$$anonymous$$s working with Unity? If you can provide a sample project where t$$anonymous$$s is working with all the steps to install, I'd be grateful! I've also raised the issue in Github, but as they might not be familiar with Unity, I thought it best to ask here too.