When you have accumulated at least 25 tanks you will have the option to enlist them in a platoon. Platoons consist of 25 or more tanks and generate staking rewards on autopilot. Tanks in a platoon generate energy tokens daily. The amount of energy tokens generated per tank is dependent on the tiers of the tanks being staked. The exact number of tokens generated per tank in each tier can be seen in the link below. For example, if you are staking 15 S tier tanks and 10 C tier tanks, you would earn 15 * 0.5 + 10 * 0.1 = 8.5 energy tokens per day.