To install the appstore app, right-click on your turtle to open the GUI, run
pastebin get iXRkjNsG appstore. To install stairminer, run
appstore get AlSweigart stairminer.
Mines the ground in front of the turtle, creating stairs down into the ground.
This program is used in Chapter 15 of Coding with Minecraft. You can view it at https://turtleappstore.com/book/chapter15.html