Determine the type of game you want to make. Review the games on TI-83 game sites to get an idea what is possible. Look at the TI-83 games given in the resources section suck as the TI-83/84 Plus BASIC Games web page at ticalc.org (see Resources). Play some games and create a game that will be easy to design and program.
Familiarize yourself with the basic input / output commands that the TI-83 offers Especially take note of the "DISP" input/output command used to display characters, numbers and pixels on the screen. Also become familiar with the "getKey" function, which is often used to design the keyboard interface for games.
Consult the TI-83 Plus Graphing Calculator Guidebook listed in the reference section to find out more about the DISP and getKey commands and the different programming commands the TI-83 offers as well as the correct syntax of commands and how to enter commands.
See the link, Texas Instruments, Learning Media: Module, 13, in the reference section to try out a virtual tutorial for programming the TI-83. Use the virtual TI-83 calculator in the tutorial there to learn specific key functions and required steps of TI-83 programming, TI-83 key sequencing, menu selection and program operation.
Plan out your game design. Decide on which keys the game player will use to control the cursor on the screen and enter values into the game. Write down what the screen will display when the game player presses one of the keys on the keyboard. Determine which TI-83 commands would be best suited for your game program processes.
Write down a generalized sequence of steps that the game will perform when the game starts, when a specific event occurs, like a certain key is pressed, when a point is scored, when you win the game and when the game is over, like an option to start a new game. Then write out the code for the program on paper.
Press the program key "PRGM" on your keyboard to start the programming process. Select the "New" option from the menu that appears on the screen. Press the "ENTER" key on your keyboard. Now press the "Catalog" key on your keyboard to access the different programming command menus. Enter in the programming code into your TI-83 that you wrote down in the previous step.