Download the ZIP file, uncompress it, open the DMG disk image and launch Vallum installer. Once finished your Mac will restart. Vallum firewall is set to automatically start at boot, use the Vallum icon in macOS menu bar, near the clock, to control the firewall.
Vallum requires macOS 10.10.5, 10.11 or macOS 10.12.
To install Vallum you need to provide the administrator password. This is mandatory in order to install a kernel extension.