How to make multi robots in ros and rviz?

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Hi everyone,

I have been trying to run ros with 2 franka robots in one rviz window. I followed this steps and it worked with gazebo with small changes. I have failed to apply this. I couldn't find any information about the rviz file format and where to add two robots (how to understand what is inside?)

What I have achieved is to get the right tf tree for two robots, nodes and topics, but still couldn't see two robots, only one (yes, their initial positions were different).

Can more experience ros users point out a direction or show how to achieve the goal?

I use ubuntu 18 and ros melodic.

Best,