Refer: https://www.ostechnix.com/create-custom-ubuntu-live-cd-image/
Install Cubic
Cubic developer has made a PPA to ease the installation process. To install Cubic on your Ubuntu system, run the following commands one by one in your Terminal:
$ sudo apt-add-repository ppa:cubic- wizard/ release
$ sudo apt-key adv --keyserver keyserver. ubuntu. com --recv-keys 6494C6D6997C215E
$ sudo apt update
$ sudo apt install cubic