Gears - Overview
Gears are basic mechanical components required for the construction of all Steam Units, and function as the fifth resource in the game that can ONLY be spent on Steam Unit construction. Gears can be produced at the Manufactory by investing Gold and Lumber. Once you've built the Manufactory, you can begin producing Gears.
To start producing Gears, go to the Manufactory and select the amount of Resources you wish to invest and click the "Manufacture" button. Gold and Lumber will always be used at the following ratio: 1 Unit of Gold + 1 Unit of Lumber = 1 Unit of Gear. (E.g. to make 500 Gears requires 500 G and 500 L)
You may also spend Rubies to instantly produce Gears. Choose the desired amount of Gears you wish to produce at the bottom of the screen and click the "Purchase" button. For instant Gear production you will need Rubies, Gold, and Lumber.
Once you've research the required Discovery and stockpiled enough Gears, you will be able to produce Steam Units and their Veteran variants.
Once you reach level 20, you can also get Gears by capturing Gear Mills (special Targets containing Gears). The amount of Gears produced by the Target and its capacity depend on its size. The higher Target's level is, the more Gears per hour it produces, and the larger its capacity.
The number of Gears you can store is limited by your Warehouse capacity. Upgrade your Warehouse to store more Gears.