Naval invasions cannot be launched instantly; they require a "preparation time".

: You must build an Intel Network in the target country first. Once the network is strong enough, you can launch the "Prepare Collaboration" operation from the Operations tab. 3. Naval Invasion Preparation

Units assigned to a (front line and offensive line) automatically accumulate a "planning bonus" over time.

: When you eventually execute the plan, these units receive a combat bonus (attack and breakthrough) based on how well-prepared they are.

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: A new UI convenience in recent updates allows you to Shift + Click certain icons to instantly prepare actions like raids. 2. Prepare a Collaboration Government (Intelligence)

If you have the La Résistance DLC (included in some versions of the Field Marshal Edition), your spies can run the operation.

: Select your divisions and look for the yellow/orange bar next to their icons. This bar fills while they are stationary at the front line.