Not able to use the topics

[Vit-A-Cuss]

Hi I'm using the plugin with gazebo, Ros Melodic and PX4 with the iris drone.
After I cloned this repository and the message one I construct the catkin workspace, I've added to the .sdf code of my drone the script:

<plugin name='libgtec_uwb_plugin' filename='libgtec_uwb_plugin.so'>
      <update_rate>25</update_rate>
      <nlosSoftWallWidth>0.25</nlosSoftWallWidth>
      <tag_z_offset>1.5</tag_z_offset>
      <tag_link>tag_0</tag_link>
      <anchor_prefix>uwb_anchor</anchor_prefix>
      <all_los>false</all_los>
      <tag_id>0</tag_id>
    </plugin>

And to the empty world the script:

<model name="uwb_anchor0">
      <pose>0 0 1.5 0 0 0</pose>
      <static>1</static>
      <link name="link">
        <visual name="visual">
          <geometry>
            <box>
              <size>0.2 0.2 0.2</size>
            </box>
          </geometry>
        </visual>
      </link>
    </model>

When I launch gazebo and PX4 I visualize the box in the world and the relative plugin in the iris drone section but I can't use the topics to visualize the data;
How can I see if I have to do something else? Should I have to call roslaunch to visualize the topics?