Serial could not response HC-05 AT Command

I am using an Uno Maker, the board with purple PVC.I did follow this youtube tutorial to try switch HC-05 salve to master , but the serial monitor wont response anything to AT command. It is all blank , I have tried restart the module and repower the board but it did not work.

Youtube tutorial :

At 0:50 it is clear that that guy doesn't know what he is doing. Go to the Martyn Currey website, and get something you can actually print on paper that was written by somebody who does.

I will try later on, thanks for the information.