For basic usage, Wireshark is very simple with good explanations.
It contains built in help guide.
Also could be found
here for latest version.
Also you can go thought sharkfests and or youtube.
Generally:
1. decide what is unique for your packet (for example: some specific ip, port, maybe protocol?). it can be combined: some ip for specific protocol.
2. define filter for it.
3. choose the interface which shall capture the traffic and start capturing.
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Michael Poroger
"Science is not only knowledge, science is also to be dare"
Shimon Peres