These are the steps I took to install lightdm:
sudo apt update
sudo apt install lightdm # I have set lightdm instead of gdm3 in the interactive menu
sudo apt install slick-greeter
sudo apt install lightdm-gtk-greeter-settings
sudo apt install light-themes
sudo apt install cinnamon-desktop-environment
After I restarted the computer, I got the following login screen:
Instead of this example image:
Why?

