The idea of this article is to provide an overview of Wireshark and some of the features it has and how to use them. You can download Wireshark for free from https://www.wireshark.org/ and view the documentation at https://www.wireshark.org/docs/.
Wireshark is what is known as a network packet analyser. It is able to capture packets from different available interfaces and then analyse the capture to understand how and what packets are transiting across a network/interface.
If you'd like to look at other types of captures you can also find sample packet captures here https://wiki.wireshark.org/SampleCaptures.