The Info Board is a small sign that is located in the left side of the room, between your Resource Plots and your Training Camps. It is unlocked when you start the game. Clicking on it lets you see your Resource Production rates, including your Unit Upkeep rate (in plastic).
It's this last number (Unit Upkeep) that is most important. Your Unit Upkeep value represents how much plastic is consumed by your troops simply by existing. Each unit of troops consumes plastic at a rate that is determined by their level. In the above example, the Unit Upkeep is -7,800 plastic units per hour, shown in green text. The more troops you have, the more plastic is consumed. The higher level troops you have, the more plastic is consumed.
The good news is that you will only lose plastic automatically if your plastic inventory (the number next to the orange plastic piece at the very top of your screen) is higher than your Resource Protection number in your Moneybox building. To see this value, click on the Details icon for your Moneybox building and look to the Plastic Resource Protection value.
Your troops will consume plastic at the rate specified by the Info Board until your plastic on hand reaches the Plastic Resource Protection value. In the above example, your on-hand plastic is 64.3k, which is less than your protected value of 280,000, so your troops won't consume any of your on-hand plastic. However, once your on-hand plastic goes above 280k your troops will automatically start consuming plastic at a rate of 7,800 units per hour until your on-hand plastic reaches 280,000.
Does this mean that your troops will die because they don't have enough plastic for upkeep? The answer is no - your troops are unaffected if you don't have enough plastic for upkeep. There are no negative consequences in this situation. Therefore: It's a very good idea to keep your plastic inventory on-hand at a value that is below your Plastic Resource Protection value. Doing so prevents you from wasting resources that you worked hard to either produce or take from other players.
What should you do with your plastic then? You can store some of it in your Shelter, however your Shelter doesn't store much. You can use it up when you get it by doing something with a plastic cost, such as constructing buildings, performing research, or creating troops. You can also share it with another corps member using the Resource Assistance function.
It's important to note that you don't automatically collect resources according to the Production rates shown on your Info Board. You must collect those resources from your Factories by clicking on them. In this way you can protect some of your plastic by leaving it un-collected. However, you will stop producing resources once they reach the maximum capacity for that resource type. You reach your maximum storage capacity in 10 hours, so you can wait 10 hours to collect resources before you stop producing them.