I played the game using a controller so the buttons will be for that, for the PC controls please refer to the manual.You firstly need to have earned enough points for an upgrade and then have purchased the 'Remote Controlled Batarang' via the waynetech upgrades section.
Once you have purchased the 'Remote Controlled Batarang
' select it via the weapons menu (d-pad selection) on the Bottom Left area. Then hold
to aim your batarang and aim at an open space and use
Once in the air you will be controlling the Batarang in first person view, use the
to move the batarang left and right and the
to lower/higher the Batarang, control the Batarang back at Batman and he will automatically
catch it. Achievement unlocked!
Here's a video to demonstrate