After installation process the system wants to know the configuration parameters. Be sure that you can hardly change LDAP tree base names so this is very important to make no mistakes.
As mentioned before you need an existing domain name [ z3r0.at ] if you want to use let's encrypt to get some free and out of the box running ssl certificates. Adding additional domain names is not a big thing but base name should never been changed and so be careful!
As you can see on downer screenshot we do add another package (DHCP Server) because we assume that we have no DHCP server in our network - if yes, turn it off and use that one from UCS.