https://github.com/LUNIServer/UniverseServer?files=1
That is the latest server version and it has never been publicly released. Support isn’t provided for setting up public servers or configuring unreleased server versions. So to answer your last question no there isn’t a guide on public servers. There are various guides on YouTube how to set up older versions.
Not quite sure what you mean by content making?

If you scroll down to the bottom of the page you will see two servers listed, they are both offline. Jonny’s isn’t coming back to my knowledge. LEGO Universe Reborn has been down for a little while but apparently is coming back here shortly.

Copy/Paste your boot.cfg to here.

You need to download LUNI server version 0.5.1 over in the downloads page and then run it. Once that is running start your server and any user/pass combo will work.

Please note most of these are all educated guesses and not facts that everyone is stating.

There are no codes/commands to spawn objects in any supported versions.

0.5.1 requires no password or username if you used it you would realize that. If you continue to lie and troll the moderators and users of these forums you will be banned.