Setting up a simulation environment

Hi, please help me. I am new

I have tried your guide on running SITL, but i am not getting the same result when running ArduSub with gazebo. Qgroundcontrol is not able to connect (i manually run QGroundControl, because after running this

it is opening gazebo, but without QGroundControl as your picture shows). Qgroundcontrol stuck at waiting for vehicle connection.

any suggestions ?