$ sudo apt-get update
$ sudo apt-get install kdeconnect-plasma 

kdeconnect-plasma is installed in your system.

Make ensure the kdeconnect-plasma package were installed using the commands given below,

$ sudo dpkg-query -l | grep kdeconnect-plasma *

You will get with kdeconnect-plasma package name, version, architecture and description in a table

kdeconnect-plasma package basic information: