Pick a limit
None of these should stop hello.py. They matter when Stage 5 arrives.
Practical limits
The phone has a floor and a ceiling.
Termux can start on Android 7. The later app-builder wants Android 9 or newer, about 3.5 GB free, and patience while the device warms up. hello.py needs almost none of that.
A little deeper: 64-bit
Most modern phones want the 64-bit Code on the Go
Bit here means how the processor counts. 64-bit is the common modern width. If a download page offers two builds, the 64-bit one is the usual choice on a phone made in the last several years. If you are unsure, wait until Stage 5 and read the official page for your device.
Next step
Under the home screen, Termux pretends to be a small Linux computer. That is why pwd and ls feel like a filing cabinet.
Next step
Termux is a small Linux room living on Android.