if its a madcat headset then
go to settings accessory settings manage bluetooth devices
hold the button for 8 seconds then it should start blinking the ps3 should scan for it
then it should appear on your screen
and it will ask for a passcode mine said just to put in 0000 as the passcode
then to make a final check to see if it works exit manage blue tooth devices and go to audio device settings and check everything
then you might have to turn it back on while playing online