You have two options:
1) Use the Nspire computer software
Since version 3.2 (mid 2012), the Nspire software (“TINCS”) includes a script editor to directly create, edit, test, and debug your Lua code from within a TI-Nspire document 🙂
It is available from the Insert menu > Script Editor .
2) Use “Luna”
Luna is an open-source community tool, created by Olivier “ExtendeD” Armand, that can create .tns files (TI-Nspire) out of a .lua file, for instance.
You can download a Windows executable on TI-Planet.
For other platforms, you can compile the source code, available at the same link.
To use it, just write in a terminal / command prompt, the path to the Lua file followed by the path of .tns you want to create:
luna.exe myscript.lua mydocument.tns
Let’s go to Part 3 now!