Question How do I copy a post (instead of moving)?

I try to moderate topic "A".
I want to open a new topic ("B"), the first post would be the last post from topic "A".
With moving it's no problem to do it. But this case I need to keep the last post in "A" too.

So, how to do it?

G'day, johnyboy43, and welcome to Kunena.

There is no facility in Kunena at this time that will automatically do this for you. The only thing that I can suggest (in the few occasions when you would like to do this) is to

1) split the subject as you would normally do and perhaps edit the first post in the new topic with a reference back to the original topic that it was split from, and

2) add a new message, yourself, at the end of the original topic that quotes the text in the new split.

Sorry, this is something "manual" that you have to do yourself. Good idea, though, but not implemented at this time.

Thanks! It' a good workaround!

How should this "reference" work in case of quotation?

When I make a quotation there is no reference link at the begining just plain text: "john wrote:".
When I'm editing the quotation, I see the username and post number between the two [], but at reading it behaves as plain text, not as a link.

The "reference link" you referred to Has no real meaning at this time ... But it could be leveraged in future. For now, I would just do whatever you can think of to make sense of how and why you need to split topics on your forum.