Rabbi Fishbain on the laws of Bar Mitzvah for Bnei Noach and the laws of Ger Katan

HaRav Fishbain, shlit"a, comments on Pirkei Avos Ch. 5 where it discusses that a Jew becomes Bar Mitzvah at 13. This leads to the question as to when does a non-Jew become a Bar Mitzvah, i.e. when is he obligated to keep the Sheva Mitzvos Bnei Noach (Seven Laws of Noah). It also deals with some of the laws of conversion. It is based on a teaching from his Rosh Yeshivah, HaRav Yisroel Zev Gustman, zt"l, which he asked to HaRav Chaim Ozer Grodzinski, zt"l, on an apparent contradiction between the Tosafos and the Chasam Sofer, based on the teachings of the Tosafos HaRosh.