Resistance Suppression Guide
If you are in a prolonged war it is necessary to handle resistance if you want to not have your construction queue filled up with destroyed factories and if you want to take advantage of the industry of the land you are occupying. The only template you need (as of now, may change with upcoming DLC) is the one linked here which consists of 5 cavalry battalions. I do not recommend researching military police as from my experience they are not necessary and frankly a waste of your research slot.
Press F6 or click the Resistance map mode to see where there is resistance and see how strong it is.
To get your divisions to suppress the resistance, the easiest way is to use the ‘Garrison Area’ command with the ‘Attempt to lower resistance’ option as seen in the following picture.
You may have noticed the ability to change the occupation policy of a country in your political overview. Your occupation policy can be changed to to be gentler or harsher. A gentler policy will result in less resistance growth in exchange for a loss in local resources, local manpower, and local factories. Choosing the Harshest policy will result in no local manpower and a higher occupation cost in political power, resistance growth will not be lessened either. The benefit of this is not losing any of the occupied industry or resources.
Choosing a harsher policy will require you to garrison more divisions to deal with the resistance.
If you have enough divisions to suppress the resistance I recommend changing the occupation policy to Harshest.