Build a turn

A turn is a sequence with boundaries. Draw at the beginning of the turn, take legal actions while the turn is open, then resolve an attack if a legal attack is chosen; only after its effects resolve does the turn end. In an ordinary turn, attach an Energy card from hand to one of your Pokémon once per turn. Neither player may evolve on their own first turn unless a card says otherwise. A Pokémon also cannot normally evolve on the turn it enters play or evolve twice in the same turn. The player who goes first cannot play a Supporter on that first turn or attack. The course does not turn a remembered rule, a digital-client behavior, or an old card into a current answer. [Source: PKM-R1, p9 Parts of a Turn; p11 normal Energy attachment/evolution notes; p12 Supporter restriction; p13 Attack and End Your Turn.]

Given a fully stated turn, sort legal actions from an action that is unavailable because of the turn boundary or the fixture's explicit condition.

Fixture (not a printed deck): It is Player A's first turn of the game. Player A was selected to go first. Their Active teaching fixture has an attack whose printed cost is already met. Player A also has one Supporter teaching fixture in hand. No effect grants an exception.

Player A may read their hand and take any actions that the current rules and the fixture permit. They may not play the Supporter or declare an attack on that first turn simply because its cost is met. The restrictions come from the turn context, not from a card's damage number. If the same player later reaches a turn where the attack is legal and declares it, resolve the attack's effects; then the turn ends. [Source: PKM-R1, p11 evolution notes; p12 Supporter restriction; p13 Attack and End Your Turn.]