Option 1 : Open and choose it in rviz.
Option 2 : Run in terminal like this:
rosrun rviz rviz -d `rospack find myCobotROS`/config/mycobot.rviz
Option 3 : add in launch file like this:
<node pkg="rviz" type="rviz" name="rviz" args="-d $(find myCobotROS)/config/mycobot.rviz"/>