What is the word for knowing how to use something (phone, car, etc), but not understanding how it works?
We may use the simplistic term :
•WORKING KNOWLEDGE — the adjective can be made WORKABLE if need be.
But I would love to use - BASICS - in all these situations.
There is a relevant term, but it refers to the object being used, not to the user. In your example, the person is using their phone as a black box. As Wikipedia says,
a black box is a device, system or object which can be viewed in terms of its inputs and outputs [...], without any knowledge of its internal workings.