When reading Shacharit alone what is the requirements to read i.e. Shema ? Amidah ? Alenu ?
ב"ה Shalom The way you asked your question, leaves room for many variables. So I will offer some of the major guidelines and if you have more specific questions you can write again. Being over Bar Mitzvah requires every Jewish male to pray the entire Tefillat Shacharit. Indeed, as you pointed out the Shema and major components of Shacharit, but saying only them, one does not fill his everyday requirement of shacharit. There are Birchot Hashachar, which are another major component, then Pesukei Dezimra which begins with Baruch Sheamar and ends with Yishtabach. This is followed by the Berachot preceding Kriyat Shema and then the Shmoneh Esreh. If a person is in a rush to catch up with the Chazan for Shmoneh Esreh or there are mitigating circumstances , there are Halachot of which parts of the Tefilla take precedent and which parts can be skipped to be completed later and which parts cannot be completed. All the best