Hello KpActual, and welcome to the forum and the game
Each order has a base difficulty expressed as 2+, 3+ etc. If you roll the die for the order and fail to meet the base difficulty, you suffer an critical failure. It seems that this part is clear.
Now, your opponent may play 1 or 2 disruption tokens if you issue an order from your command station. These disruption tokens increase your difficulty by one point each. So an order with a base difficulty of 2+ becomes 4+ if your opponent plays two order tokens. Now, your odds look like this: if you roll a 1 (fail to meet base difficulty) you suffer a critical failure as normal, but if you roll a 2 or 3, you suffer just a failure, since you did manage to beat the base difficulty, but failed to roll enough to perform the order.
I hope this makes it a bit clearer?