Install slim by entering the following commands in the terminal:
sudo apt update sudo apt install slim
Description:
desktop-independent graphical login manager for X11
SLiM aims to be light, simple and independent from the various desktop environments. Although completely configurable through themes and an option file. It is particularly suitable for machines that don't require remote logins.
Homepage: http://sourceforge.net/projects/slim.berlios/
Version: 1.3.6-5.1ubuntu1
Section: universe/x11