Bluetooth module not receiving commands

I am going to make a bluetooth contolled car and i bought a bluetooth module with both master and slave mode . When i connected an app(arduino bluetooth rc control) to make it work but when the module got connected it went off no led was blinking on the bluetooth module . Should i enter ‘at’ command to go to slave mode. If yes how to do it.

bluetooth module - hc 05

please send the reply as soon as possible