To run programs on the TI-89 Titanium, access the var-link screen by pressing 2nd and the minus key. Highlight the desired program with the arrow keys and press enter to bring it to the Home screen. The program will appear in the format directory_name/program_name(. It's crucial to close the parenthesis after the program name to avoid syntax errors; for example, it should look like directory_name/program_name(). If pressing enter takes you to the apps screen instead of the Home screen, ensure that the program is correctly highlighted. There may be compatibility questions regarding TI-89 Basic edition programs on the TI-89 Titanium, but the discussion indicates that the programming learned on the TI-84 may not directly apply to the TI-89 series. If there are errors in the program, the editor should open to show where the issue lies.