No problem about your post, if there’s a better location to place the post, then we’ll move it to the appropriate thread. Congratulations on your first post!
As for your question, in order to get meaningful information on a wireshark capture device, you’ll have to configure SPAN or RSPAN on the switch on which you are connecting. You can read more about these in the lesson of this thread, however, suffice it to say that SPAN and RSPAN allow you to copy traffic (frames and packets) of particular ports or VLANs to a monitoring port (simply a switchport with a specialized configuration) so that the wireshark software can collect and store the data. Concerning the physical placement of wireshark, it’s a good idea to connect it to the switch that is directly connected to the device that you want to monitor. For example, if you want to monitor traffic going through R3, then the placement of the wireshark device is good, but you’ll have to configure SPAN.
If you want to capture all traffic that is traversing the link between Ethernetswitch-3 and R3 for example, then you will have to configure SPAN on Ethernetswitch-3 to copy all incoming and outgoing data on the E1 port to the E2 port.
Review the lesson of this thread for further details, and if you have any more questions, you know where to find us!
I hope this has been helpful!