They propably slip explanation to the question like “Good, then we can open the account”

Seems a good one.

I want to test this for awhile and show to friends.

Short answer = Nope.

PlugOS does not run in the phone, but in the thumb device named PlugMate.

Running OS in any phone is not possible as bootloaders are tailored to specific SoC:s and proprietary to manufacturers and they really do not share the sources.

If it would be possible we would have quite wild mobile phone linux scene.

Don Rosa - The Curse of Nostrildamus