If the copied artifact had {X} in its mana cost, X is 0.

If the copied artifact was a token, the token that’s created copies the original characteristics of that token as stated by the effect that created that token.

Any enters-the-battlefield abilities of the copied artifact will trigger when the token enters the battlefield. Any “as [this artifact] enters the battlefield” or “[this artifact] enters the battlefield with” abilities of the copied artifact will also work.

If the copied artifact was copying something else when it was last on the battlefield, then the token enters the battlefield as whatever that artifact copied.

The token copies exactly what was printed on the original artifact and nothing else (unless that artifact was copying something else or was a token; see below). It doesn’t copy whether that artifact was tapped or untapped, whether it had any counters on it or Auras and Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on.