20210210_raspi_4_buster.img - howto boot in graphics mode

[martin <martinatlivedotcom@live.nl>]

This morning I downloaded this image 20210210_raspi_4_buster.img from 
https://raspi.debian.net/verified/ and installed it on a sdcard. All 
looks well in console mode, so I installed KDE and did run adduser to 
create a normal user. But now I cannot find out how to boot into 
graphics mode. There is no good old startx but the sddm login is in 
/etc/init.d. I tried to start it but I don't get any reaction. So my 
question is:

How do I boot into graphics mode?

Thanks in advance,
Martin.