To receive Thulium, you must first go to the Stock Exchange to trade Fuel and Munitions.
Go to the Stock Exchange to begin exchanging Resources for Thulium. The amount of Resources you choose is completely up to you. Exchange both 500 Fuel and 500 Munitions, and in just 1 hour you will be given 500 Thulium. The exchange ratio is always the same; however, selecting shorter periods of time will increase the speed at which your trades are returned and you are rewarded with Thulium. Simply choose the desired amount of Thulium and click the "Purchase" button.
You may also choose to spend Diamonds to instantly exchange Resources for Thulium. Simply choose the desired amount of Thulium you wish to get and click the "Purchase" button. For instantaneous exchange, you will need Diamonds as well as both Munitions and Fuel.
Once you've negotiated the required Contracts and amassed enough Thulium, you will be able to hire "Viper" CQB Assault Troopers, "Rhino" TAG Defense Troopers, "Vector" Heavy Infantry Troopers, and the "Cheetah" R-TAG Assault Troopers. These Units can be hired via the Units menu.
The amount of Thulium you can hold is limited by your Storage Depot capacity. Upgrade your Storage Depots to store more Thulium.
Once you reach the required level, you can also get Thulium by capturing Thulium Deposits scattered all over Zandia.