I'm trying to conserve move actions with my 300 pt. team.
When I use perplex, does it cost me a move action?

After I a attack a target , can I perplex the damage up ? Or do I have to declare it before the attack?

Perplex does not cost an action to use.

It may be used BY a figure with 0, 1 or 2 action tokens assigned to it.


It may be used ON a figure with 0, 1 or 2 action tokens assigned to it.

Perplex has to be declared before the actual attack action is declared.

So, no. You cannot Perplex the damage up after you successfully attack the target.