you cannot create an instance of MethodBase because it’s an abstract class,
TH1D is not part of the TMVA namespace,
`TMVA::TH1D h2&’ is not a valid parameter.
Maybe the TMVA users guide root.cern.ch/root/html/TMVA_Index.html will help with the first problem. You should (really!) learn C++ to solve the other problems. There is no way that you can use ROOT or TMVA without knowing the basics of C++.
Walter Brown will be offering a “Beginner’s Accelerated C++” class in July at CERN and August at FNAL. I know many people who have taken it and recommend it. I second Axel’s comment that one will be much more productive in Root with a better knowledge of C++.