The instructions for entering, running, exiting, and editing are the same for any program. The actual program on this sheet allows you to quickly evaluate a function. This may be helpful when determining a reasonable window for graphing or investigating the value of a limit.
Information that is printed within {} is not typed into the calculator. Usually this contains instructions for finding a particular command. Anything in RED denotes a button on the calculator. For example + is the addition button. Anything in BLUE denotes a button on the calculator that requires hitting another button first. For example the QUIT command will appear here as QUIT because you need to hit the 2nd button first.

Your calculator manual will be very valuable for finding the commands and buttons needed for programming. If you have misplaced yours, visit the TI website to view a copy. TI Manuals

If you have a TI Connectivity Cable, you can download the program main.eval.89p

How to enter a new program

Any words in the program that begin with an uppercase letter (Disp, for example) are actually commands. These models allow you to enter both uppercase and lowercase letters. That means you can type in the entire program letter by letter. But all commands can be found easily using CATALOG. To move quickly through the catalog, type in the first letter of the command you want to retrieve. You will move to the portion of the catalog that contains words starting with that letter.

The Program

This program has seven lines. Three lines will automatically appear. Hit ENTER at the end of each line. When you are finished, hit HOME.
:eval( )  {this will already appear assuming you named the program eval}
:Prgm  {this will already appear}
:Lbl p  {Lbl is in the CATALOG menu}
:Prompt x       {Prompt is in the F3 menu} {x is the X button}
:Disp y1(x)  {Disp is in the F3 menu} {y1 is the Y button followed by a 1}
:Goto p  {Goto is in the CATALOG menu}
:EndPrgm {this will already appear}

How to run the program