Hi @KTBE ,
You can change the Fixed Frame in Rviz by clicking it on the Displays Properties on the left side panel.
On your picture, you currently see “map”. Double click on this map and change it to something else, that you can find in the dropdown.
You should probably also add RobotModel and TF in your RViz to actually visualize the model.
I hope this helps. Let me know if you still have issues.
Regards,
Girish