var file = new FileInfo("modinfo.json");
IModinfoFile modinfoFile = new MainModinfoFile(file);

IModinfo modinfo = modinfoFile.GetModinfo();

var dir = new DirectoryInfo("YourModPath");
ModinfoFinderCollection result = ModinfoFileFinder.FindModinfoFiles(dir);

IModinfoFile mainFile = result.MainModinfo;
IEnumerable<IModinfoFile> variantFiles = result.Variants;

var file1 = new FileInfo("modinfo.json");
IModinfoFile mainModinfoFile = new MainModinfoFile(file1);

var file2 = new FileInfo("varaint-modinfo.json");
IModinfoFile variantDerived = new ModinfoVariantFile(file2, mainModinfoFile);