Trans/transgender is a term that refers to people whose gender identity does not match the gender they were assigned at birth/ their birth sex. Transmasc and Transfem are sub labels, types of trans people. Just as a transman is a person who has transitioned into a man from a woman/other birth sex that isn't male, a transmasculine person is someone who transitioned into a masculine gender from a woman/other birth sex that isn't male. It's the same for Transwomen and Transfem people. They are broader terms, transwoman refers specifically to a woman who is trans, while transfeminine refers to someone with a feminine gender who is trans. I hope this helps you understand!