Once the box is checked you can end your turn and characters who haven't moved yet will automatically attack.
Viewing post in Auto Attacks
thanks, that worked. i normally attack with everyone in my party (no reason not to) so it is no wonder i never could figure out why this wasnt working.
when i was thinking autoattack on clicking it i was thinking how most other games i have seen implement it. which is at the start of the turn your units begin attacking on their own until you are out of actions. then it automatically ends the turn as well and continues until you either stop it or battle ends.