Step-by-Step Guide: Hold any amount of TRC-20 based USDT in your private wallet or supported exchanges. TRON Foundation will airdrop a total of 30,000,000 USDT to eligible wallets. The airdrop will start from July 15, 09:00 to August 15, 08:59. The holders will receive airdrop bonus on a daily basis. The rewarded amount is calculated based on your TRC20 USDT Balance * APR / 365. APR means Annualized Percentage Rate. APR on the first day of the airdrop is 100%. So if you hold $1000 USDT-TRON then it will get calculated into $1000/365 = $2.74. For more information regarding the airdrop see this post.