If the copied permanent has in its mana cost, X is considered to be 0.

If the copied permanent is a token, the new token that's created copies the original characteristics of that token, with the exceptions noted above.

Except for power, toughness, types, and the flying ability, the token copies exactly what was printed on the original permanent and nothing else (unless that permanent is copying something else or is a token; see below). It doesn't copy whether that permanent is tapped or untapped, whether it has any counters on it or Auras and Equipment attached to it, and so on.

Since the tokens are creatures, they can't attack or until your next turn if they don't have haste.

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

If the copied permanent is copying something else, then the token enters the battlefield as whatever that permanent copied, with the exceptions noted above.

If you target an Aura with Astral Dragon's ability, no tokens will be created.