Since Plasma works on lightdm now as login or display manager we need to edit the lightdm configuration file. More technical info at Arch Wiki.
Let us open up /etc/lightdm/lightdm.conf and change one word from xfce to plasma and save it.
You can see what I changed the above picture. (blue line)
That is all it takes.
You can follow our tutorials based on either of two iso's.
1. ArcoLinuxB Plasma (recommended)
We record the plasma video's on an SSD installed from the ArcoLinuxB Plasma iso.
You can either create your very own ArcoLinuxB Plasma iso following this tutorial or download it from Sourceforge. (ArcoLinuxB-plasma-18.11.2.iso of 4.3 GB - games included)
2. ArcoLinuxD Plasma
You can also use the ArcoLinuxD iso and then install Plasma with the help of the github scripts. This will not be an exact copy of the iso.
Learn about the Plasma desktop and enjoy it.