pkg is the installer inside the room
A package is an add-on you install inside Termux, the way you install an app on the home screen. Python is a package. Git is a package.
pkg install python nanoThe typed room
Dark screen. Prompt. That is normal.
Termux is an app that gives your phone a terminal. You type commands instead of tapping icons. It looks old. This is how programmers talk directly to the computer.
This page is the explanation. The install walk is Stage 2. pkg lives here when you forget what it means.
Wrong copy
If you installed Termux from Play Store, uninstall it. Install Termux and Termux:API from F-Droid only. Same store for both.
Next step
The helper app and the package work as a pair.