Familiarize yourself with the TI-89 keyboard. Note that the TI-89 calculator is arranged in a matrix of ten rows and five columns of keys. Note also that the four screen cursor control keys (which have an up, down, right and left arrow on them) are located on the upper right hand side of the keyboard, just below the first row of keys.
Press the "HOME" key on your keyboard (1st column, 4th row on your keyboard). Press the "MODE" key (2nd column, 4th row).
Move the screen's cursor to the "Graph" menu option. Press the "right cursor" arrow. Scroll down to the "3D" option, also referred to as the "number 5" option. Press "ENTER" on your keyboard (5th column, 10th row) to set the mode to 3D.
Press the "Diamond" key (1st column, 3rd row) and then press the "F1" key (1st column, 1st row) to display the equation editor on the screen.
Scroll to the first "Z" equation in the equation editor that appears. Press the "y" key (5th row, 2 column). Press the "exponent" key (5th row, 5th column). Press the "2" key (9th row, 3rd column). Press the "minus" key (8th row, 5th column). Press the "x" key (5th row, 1st column). Press the "exponent" key again and press the "2" key again to complete entry of the equation z1=y^2 - x^2. Press the "ENTER" key (10th row, 5th column) to store the contour equation in the TI-89's memory.
Press the "F1" key (1st column, 1st row) and then press the "9" key (4th column, 6th row) to display the graphic format menu on the screen. Move the screen cursor over the "Style" option and press the "right cursor control" key to select the type of 3D graph. Move the screen cursor over the "CONTOUR" option and press the "ENTER" key (5th column, 10th row) to set contour map mode.
Press the "diamond" key (1st column, 3rd row) and the "F3" key (3rd column, 1st row) to graph the contour equation on the screen.