This is a very broad question. Start by looking for existing literature that describes molecular phylogenetic analysis of pteromalid wasps or their closest wasp relatives. Study the methodology of these authors and refer to their references to learn more about the methods. Then find a methodology book: 'Molecular Evolution: A Statistical Approach' Ziheng Yang, 2014; Tree Thinking: An Introduction to Phylogenetic Biology, Baum and Smith, etc.