Houston should detect or tell you if Samba is installed on the system.
It seems you are using Ubuntu 20.04 LTS rather than the pre-built install which ships Rocky Linux.
There is a separate post sharing the detail to get Samba working on the pre-built system
In the thread (which worked for me as I am using Rocky), the cockpit ZFS manager’s settings were changed to reflect what Hutch suggested on the post… As I am not using Ubuntu 20.04, I can not give you the exact details as I don’t know what you have installed/configured on the system.
The key parts is to make sure the Cockpit Manager does not try to add includes as that was a problem with the Rocky system.
Samba does not like the workgroup name being the same as the netbios; these prebuilt machines have the unit’s host name as HL15.
What have you attempted or completed? Or was this post to gather details on how to do it?