I haven't been able to find a good TUTORIAL for TIBasic (The programming language used on TI-8x Calculators). I have found Tips, and Idioms, and forming Good habits, but i haven't been able to find an actual TUTORIAL on it. I have made a game of sorts, and I am hoping to incorporate graphics into it soon. I am going to check the Texas Instruments site for it, but I have had no luck previously.
On the one I have it shows two example programs which should give you an idea on how the syntax works.
And Appendix A shows every function/keyword that the calculator supports and what they do
It contains everything you need to start programming