As you may know, Grub Customizer is a nice application, that allows the user to edit the menu entries from the GRUB booting screen, set the default operating system, change the installed OS via a livecd.
The latest version available is Grub Customizer 5.1, which has been released a while ago.
In this article I will provide you detailed instructions on how to install Grub Customizer on Ubuntu 18.10 Cosmic Cuttlefish, Ubuntu 18.04 Bionic Beaver, Ubuntu 16.04 Xenial Xerus, Ubuntu 14.04 Trusty Tahr and derivative systems.
Because it is available via PPA, the installation instructions are quite straight forward. All you need to do is add the PPA to your system, update the local repository index and install the grub-customizer package. Like this:
$ sudo add-apt-repository ppa:danielrichter2007/grub-customizer
$ sudo apt-get update
$ sudo apt-get install grub-customizer
Optional, to remove grub-customizer, do:
$ sudo apt-get remove grub-customizer