For Volibear's attack ability that deals 5 damage, when do you choose targets and assign damage - before the trigger resolves or when it resolves?

Ruling: When Volibear attacks, the trigger goes on the chain and you choose targets at that time. When the trigger resolves, you then assign the 5 damage between the chosen targets (must assign at least 1 damage to each).

Sequence:

• Attack with Volibear, trigger goes on the chain
• Choose targets for the damage
• When trigger resolves, assign the 5 damage between chosen targets

Nuances:

• You must assign at least 1 damage to each chosen target
• Because targets are chosen before resolution, opponents can respond by buffing units before damage is assigned