How to run multiple darknet_ros simultaneously?

edit

Might be a beginner question but how can i possibly run two or more darknet_ros node simultaneously which publishes different data from something like:

/darknet_ros_leftcamera
/darknet_ros_rightcamera
/darknet_ros_uppercamera

I've created multiple /usb_cam_*** nodes which publishes different images from separate cameras simultaneously. Then i tried to create different launch files in one darknet_ros folder and edited them one by one so each one should connect separate cameras

<arg name="image" default="/usb_cam_1/image_raw" />

and different node names for each launch file (I'm definitely not sure)

<node pkg="darknet_ros_1" type="darknet_ros" name="darknet_ros_1" output="screen" launch-prefix="$(arg launch_prefix)">

but whenever i launch the second launch file, the other one closes and the last one opens that i couldn't make them run at the same time.

I am absolute beginner on ROS so i'd be so happy to find a solution!

Thanks
Emre