Could you please describe your use case?
What exactly do you want to achieve?
Zammad is not a Forum-like software where you could create topic. If you mean topic==Ticket, then it depends on who you are in terms of for Zammad (Customer or Agent).
By default you have a big green “+” on the lower left side which allows you to create new tickets.
If you mean departments as in groups, you can find them in the Backend (Tool-Gear) in “Groups”.
As for countries I have no idea what you want to do here. Sorry.
The second one: No, Zammad has no way on determining on where the ticket came from (as in “country”). What you can do is to create a user object “country” which you or your user needs to prefill.