Ubuntu Server for RockPi4B 4GB

Hi,
need help to install ubuntu server on my Pi4. After installing the desktop (mate) it doesn’t starts automatically. After rebooting i have to type login and password and only prompt appears. Can somebody help me? I use this iso-image (https://wiki.radxa.com/Rockpi4/downloads - ubuntu server). I’m a absolute beginner and try to ran later kopano.

apt-get install ubuntu-desktop

P.S. or you may try this

Did you use this or a similar command?
sudo apt-get install mate-desktop-environment-extras

I don’t no why but now it works…
I see now Ubuntu mate.
Thanks!