Could someone please explain castles for me? - How you get them? What they in effect do? I take it there is a defensive bonus and an associated potential negative for an army attacking them?
I'm in a multi player and they seem to have popped up in lots of other players' territories. Do i need to earn a card to get them or something?

Do you mean cities?

If so, the game has commerce enabled, see: https://www.warzone.com/wiki/Commerce

I'm not sure. I don't think so. I'm on a Scandinavian massive map massive multi player game.Sure the notifications said players were setting castles in various linked territories.

Perhaps the game has some mods?

Could you link the game so we can have a look?

Certainly. Except my tech skills are so pitiful im not sure how to do that!?

Sorry about this;thanks for trying to help. - I have asked for advice in the same manner in the game in question, but...even though there're around twenty players no one has so much as acknowledged the query...!

Like 99% certain you are talking about cities (that looks like castles on the map if you will).

Top left, under the Deploy / Attack menu, there is a gold bar. Click it. Build cities.

To get a game link:

If website: copy the URL.
If app: Settings > Full Settings > Game link (try to copy this)

Ah.Okay. Thanks guys. Will keep my eye on the action history window thingy and see if i can catch the name of what they're all building. Is it one goldbar per castle.

Thaks for the advice on copyand pasting/providing links. I may need your advice again shortly.

Thanks again guys, much appreciated.

Definitely cities.

Thanks for your help guys. It was indeed cities(of course it was!).