As it seems right now the players need to manage their clans separately from the Faction UI (which is really nicely implemented, well done).
It would be even better if the Faction UI can trigger creation of Clans when using that plugin automatically, instead of having player type commands.

I'm playing around with it a little but not yet found a simple solution to make it work.

Sadly the Clans plugin does not have hooks to create and modify clans, only hooks to notify when clans are created/modified and read the current data.

I only integrate with whatever the other plugin developers made available through API/hooks in their docs. If the Clans plugins ever happen to get hooks for clan creation and manipulation in the future then I certainly can do that.