Ambush, gain flank later in the game

Not sure how this card should be played.
Can I just play it at any time, removing the chosen models from play and deploy them later as subscribed?
Or are there conditions that need to be met for them to be removed from play? If so, how do I do this?

Cheers for any help.

Gaining the Flank trait during the game does nothing unless the card also tells you to place the model elsewhere. So you need to play Ambush before deployment or it will have no effect.

This has been confirmed by a developer on discord.

Master Enos: Unless you play any of the three Ambush cards before deployment, they won't do anything.

By Mcgreag

That makes sense. Thank you

By The_Voivod
yenohoney