1. download Wireshark from https://www.wireshark.org/ (most likely, the Windows installer (64-bit)). the current version is 2.6.0.
2. open the installer file (Wireshark-win64-2.6.0.exe, most likely).
3. keep the default components to be installed, but you may add the Desktop Icon on the next screen.
4. choose a different installation folder, if you C: drive is too fat.
5. Yes, install WinPcap (or Npcap), it is needed.
6. No need for USBPcap now, click the Install button.
7. WinPcap installation kicks in, don't set it to start automatically, it's a service you don't need, most of the time.
Installation is over, good luck using it!