The Lottery happens at the top of each hour and selects a random player who was online during the previous hour to win various rewards. To be entered you need to have been online at any point during the hour beforehand, you don't need to be online specifically at the top of the hour. If you win the Lottery you will get a notification saying that you won, and what rewards you received (the rewards are given to you automatically). The rewards from the lottery are as follows:

• 2% chance to win 1000AC-5000AC
• 98% chance to win 50AC-1000AC

PS. Please feel free to ask in chat if you're unsure of how to spend your lotto (especially a super lotto).