Any enters abilities of the copied creature will trigger when the token enters the battlefield. Any "as [this permanent] enters" or "[this permanent] enters with" abilities of the copied creature will also work.

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

If the copied creature is a token, the token created by Face Yourself copies the original characteristics of that token as stated by the effect that put that token onto the battlefield.

If the copied creature is copying something else (for example, if the copied creature is a Clone), then the token enters the battlefield as whatever that creature copied.

The tokens copy exactly what was printed on the original creature, with the listed exceptions, and nothing else (unless that permanent is copying something else or is a token; see below). It doesn't copy whether that creature is tapped or untapped, whether it has any counters on it or Auras and Equipment attached to it, or any non-copy effects that have changed its power, toughness, types, color, and so on.

The tokens see each other enter the battlefield. If any of them have a triggered ability that triggers whenever a creature enters, they'll trigger for one another.