Need help understanding Fight sequence

[kabaakaba]

Starting with the attacker, the players alternate resolving one of their successful unblocked attack dice. The players repeat this process until one player has resolved all their dice (in which case their opponent resolves all their remaining dice), or one operative in that fight is incapacitated. When a player resolves a dice, they must strike or block with it.
lf they strike, inflict damage on the enemy operative, then discard that dice.
A normal success inflicts damage equal to the weapon’s Normal Dmg stat.
A critical success inflicts damage equal to the weapon’s Critical Dmg stat.

If they block, they can allocate that dice to block one of their opponent’s unresolved successes.

A normal success can block a normal success.
A critical success can block a normal success or a critical success.

I don't understand how first strike should be resolved. 
if attacker choose strike it's inflict damage or wait if defender decide to block or not to block.