Each turn the players propose what happens next in the game, giving reasons for why their proposal is likely to happen. The ref assesses the proposals based on how likely they are to happen, and they succeed or fail with a die roll. Failed proposals disappear. Successful proposals actually happen, creating a story as we go along.
Proposals can be about anything, but proposals that make sense, build on facts in the story from the starting situation or from previous successful proposals, and have good arguments in their favor are most likely to succeed.
A proposal normally takes the form of action / result / reasons. For example:
action: First squad occupies the town of Hicksville. They use the MMG and LMG to set up an ambush with interlocking fields of fire. The riflemen are deployed in concealed locations to prevent the enemy from flanking the MGs. A concealed observation post is established in the bell tower of the church. The Lt. and sniper are posted there.
result: We have a concealed ambush in the town which the enemy doesn't know anything about. Any attempt to pass the town or use the nearby road will trigger an ambush.
1. We have a veteran NCO in the squad that knows how to set up an ambush.
2. We are positioned close to the town, so it's not a difficult move. We can move through the forest to conceal our movement. The town is currently unoccupied.
If successful all the details of the action become part of the story, facts. They can be used for later arguments. You can make proposals about anything, so if the enemy doesn't come near the town that's ok. You can make a proposal that they do, and get ambused, because you can make proposals about anything, including the actions of the other side. Of course you'd need a good reason for why they'd move into town, maybe it's a strategic crossroads they'd want to control. Maybe they are low on supplies and go to town to look for food. Whatever you can think of. You're only limited by your imagination, and of course logic.