How to Install KDE Plasma Desktop Environment on Linux Mint 21 KDE Plasma Desktop

E: Unable to locate package kde-desktop-full, not able to install is there something i can do

How can i update ?

How do you install the latest 5.27 version?

am new to linux, what is the difference between sddm and lightdm? and which should I choose

Lol just gotta love how customizable Linux really is. Everything is accessible so easily down to the kernel it's self.

Will installing plasma overwrite or affect the currently installed cinnamon desktop?

THIS same thing would work for LMDE5 too-- right-- debian based -- or are the commands too different??