I've tried to give some idea of the keys on the TI without making it impossible to type. bnb stands for the button next to the book icon on the TI, which contains the mod function, integrals, and matrices.
v stands for the two-dimensional vector within bnb, m stands for the multiple rows and columns matrix button (with the picture of a 3x3 matrix).
The line meaning "given that" is got by ctrl = on the calculator, and is next to the shift key on computer keyboards.