click on the proceed with installation. When asked about installation options, select only the one saying "Install Npcap in WinPcap API-compatible Mode"
Please note that if you used other tools with network-scanning capabilities before (e.g. Wireshark) you might have also installed a library called Win10Pcap. Make sure that this library is not installed in your system. Once you have installed Npcap, you can proceed with the installation of the AngelBox Compatibility Tester. It is possible that you will have to disable your anti-virus tools to install and use the compatibility tester.
Currently, there are installation packages for two major Linux distributions. Ubuntu and Fedora. You should use the corresponding version of your distribution.