On my linux-journey I learned the following last weekend:

In order to use a display manager to login, instead of the command line, you just need to change to following line in /etc/inittab

# Default runlevel. (Do not set to 0 or 6) id:3:initdefault:

to

# Default runlevel. (Do not set to 0 or 6) id:4:initdefault:

The next time you boot you’ll see this.