How exactly does a bracket order work?

TODAY WAS MY FIRST DAY OF TRADING .ISTARTED WITH CURRENCY .

I PLACED A BRACKET ORDER AT ABOUT 10:44 AM .

THE MARGIN USED WAS 388 APPROX.

I WAS HOPING THE POSITION WILL SQUAREOFF ON ITS OWN AT 3:20 PM .

WHEN I LOGGED IN AGAIN 4:40 PM I SEE IN ADMIN POSTION THAT ALONGIWTH BO AND MIS ORDER IS ALSO PLACED (i did not place this order).

AND MY CASH POSITION SHOWS MARGIN USED IS 1288 .

how is this possible ?

what exactly happened ?

customer support says to wait till 6:30 pm to get exact cash position ?

Btw, currency markets are open till 5pm and hence all MIS square offs happen by 4.30pm.