Turn order question

Hey guys,
Tried to find this somewhere else, but can’t seem to find anywhere.
Is there a set structure to turns other than you attacking first?
This came up with a situation the other day.

Raiding with only my proteus alive- 14 hp(no buffs or debuffs)

Opponent has boril alive- 28 hp (counter attack up and proteus DOT) ready to attack
Basically boils down to is there a recognizable system for how a turn follows
Option 1: fire at him and get countered. (Did this, and died) figured that my dmg would kill and the match would be over. Instead we both died, tie goes to defense
Option 2: miss, he attacks and kills me, dot, kills him, tie goes to defense.
Obviously i was caught in a no win, but the instance highlighted that i haven’t seen precise workings.
Does the turn order go:
Action option- you

Tile- you

Buff/ debuff reactions

Opponent actions

Buff/ debuff reactions

Opponent direct dmg

Buff/ debuff actions (dots)

End of turn and clean up with buffs and debuffs dropping off