Linux Shout published a tutorial about how to install Zenmap Nmap GUI on Ubuntu 20.04 LTS.
How to install Zenmap Nmap GUI on Ubuntu 20.04 LTS
Learn the simple steps to manually install the latest verion of Zenmap on Ubuntu 20.04 LTS focal fossa Linux, a GUI for Nmap network scanner.
How to install Zenmap Nmap GUI on Ubuntu 20.04 LTS - Linux Shout