I'm running KDE but i want install another Desktop

Gnoppix Desktop environment


	The GNOME project provides two things: The GNOME desktop environment, an intuitive and attractive desktop for users, and the GNOME development platform, an extensive framework for building applications that integrate into the rest of the desktop.
	Plasma by KDE is a powerful open source graphical desktop environment for Unix workstations. It combines ease of use, contemporary functionality, and outstanding graphical design with the technological superiority of the Unix operating system.
	Xfce is a lightweight desktop environment for various *NIX systems. Designed for productivity, it loads and executes applications quickly, while conserving system resources.
	LXDE is designed to work well with computers on the low end of the performance spectrum such as older resource-constrained machines, new generation netbooks, and other small computers.
	MATE is the continuation of GNOME 2. It provides an intuitive and attractive desktop environment using traditional metaphors for Linux and other Unix-like operating systems.

Other desktop environments available in Gnoppix Linux include Cinnamon, LXQt, Budgie, Enlightenment, FVWM-Crystal, GNUstep/Window Maker, Sugar and possibly others.

Open a terminal or konsole and run : sudo apt install tasksel && sudo tasksel

A user on Gnoppix 23 through Gnoppix 24 would be presented with the menu:

[*] Debian desktop environment
[ ] GNOME
[ ] Xfce
[ ] KDE Plasma
[ ] Cinnamon
[x] MATE
[ ] LXDE
[ ] LXQt

Accepting this selection installs the MATE desktop environment.
Without deselecting the desktop environment, another entry, GNOME included, may be selected. This will install that selection.
Unticking Debian desktop environment and selecting a desktop environment leads to the Gnoppix desktop environment set being installed.

For an explanation of this behaviour, we have to look at part of the Recommends: line in apt show task-desktop.

Recommends: task-gnome-desktop | task-xfce-desktop | task-kde-desktop | task-lxde-desktop
            | task-cinnamon-desktop | task-mate-desktop | task-lxqt-desktop

The Gnoppix desktop environment option installs task-desktop and requires one of the packages listed above. If none of them are on the system, the first in the list, task-gnome-desktop, will be installed to fulfill the dependency. This is the situation when a user accepts only the Gnoppix desktop environment.
Looking at apt show task-mate-desktop we see that it depends on task-desktop and mate-desktop-environment. Ticking MATE, with or without the Gnoppix desktop environment ticked, would satisfy task-desktop's Recommends: line and install MATE instead of the GNOME default.