We have listed the following useful information at https://www.ti89.com/resources.php :
TI89 Cheat Sheets
Shortcut Keys
Custom Menus
Rename Programs
This is a MUST KNOW for every savvy TI89 user: Learn how to use the TI89 efficiently by pressing the right buttons without searching. Did you know you can actually easily create you own custom menus that allow you to access common commands at a heart beat? Lastly, who does not love shortcuts? Do you know how to darken the screen? Do you know how to get a a factorial symbol or how to get decimal answers quickly? Well it is all laid out right here:
https://www.ti89.com/resources.php