server – Spacewalk 2.10 add ubuntu client 14.04 16.04 18.04 20.04

I have installed a spacewalk server 2.10 and created channels and repositories for my ubuntu servers 14.04, 16.04, 18.04, 20.04.

How can I connect my ubuntu servers 14.04 16.04 18.04 20.04 to my spacewalk server 2.10?

Thanks in advance.

Best regards ;]