Purchase at Ministry of War using a Rixty account:
To see screenshots, click numbered paragraphs at left
Log-in to your account (usually located on the main page)
Now locate the store, which is where you can purchase in-game currency (each game has its own name for their “store”, or might have “Buy credit/coin/etc.” instead)
Locate the Rixty logo in the payments page, click; now, select the amount of currency you want to purchase, click to continue
Login to your Rixty account and complete the purchase. If you need to add funds, click a payment method and follow the prompts.