There are two separate slots which you have to open by researching them in the Research Facility.
Supplies have 3 properties:
Buff, or the bonus it gives while being equipped
Duration, meaning the moment between equip and destruction
Level - supplies are upgradable. Their level affects the buff, supply duration and cost of upgrade.
When clicking on one of the Supply Slots, you will see listed all the Supplies you have in your inventory.
The Supplies and the bonuses they give are the following:
Bandages - Gives Unit Hitpoints bonus
AP Rounds - Gives Unit Attack and Enemy Defense Debuff bonuses
HE Rounds - Gives Unit Defense and Enemy Attack Debuff bonuses
Tea Ration - Gives Infantry Attack, Defense and Hitpoints bonuses
Canned Meat - Gives Field Artillery Attack, Defense and Hitpoints bonuses
Coffee - Gives Cavalry Attack, Defense and Hitpoints bonuses
Boiled Sweets - Gives Enemy Hitpoints Debuff bonuses
Chocolate - Gives Unit Attack and Rally Attack bonuses
Spare Socks - Gives Infantry attack, Field Artillery Attack and Cavalry Attack bonuses
Biscuits - Gives March Speed and Unit Attack bonuses
Toothpaste - Gives Tech Monsters March Speed and Field Artillery Hitpoints bonuses
Soap - gives Gathering Speed and Gathering March Speed
Cigarettes - Gives Gathering Speed and Gold Gathering Speed
Shaving Kit - Gives Rally Attack and Rally March Speed Debuff bonuses
Supply level-up
If you press the “Details” button, you will see all the Levels of the supply.
When upgrading the Supply, you can check out the required supplies amount and the cost.
Keep in mind that upgrading Supply and Equipment items at the same time is not possible.
Unlike Equipment, in order to upgrade Supply to the next level, you will need a certain amount of supply of the inferior level.
For example, if you start with 4 x level 1 Bandages, after upgrading, you will have 1 x level 2 Bandages and 2 x level 1 Bandages.
In order to make a level 3 Bandages, you will need another level 2 Bandages made from the 2 x level 1 Bandages.
The Quick Equip button will equip your Commander with the highest leveled supply. If you wish to save the highest-leveled supply for a more important battle, you need to press “Details” and equip a lower-leveled supply.
If you remove the supply, the timer will still run but the bonuses are not added. Once the timer runs out, the item is destroyed.
Once you unlock the second slot for supplies, you can activate a second supply item at the same time. You have the possibility of equipping the same level, same supply twice.
You can purchase Supplies Chests from the Store (Store > Chests) or you can win them. Supplies Chests can be obtained when clearing resource tiles, in battles or as rewards in Events.