It means the profit or loss on a movement of 0.01 in the futures price is $12.50 per contract. (3/12 x 0.01% x $500,000 = $12.50).
These are both explained in full in my free lectures (and you never actually need to use ticks in the exam).
Opening and settlement have only been mentioned once in the exam (by the previous examiner). Opening is the price at the start of the day; settlement is the price actually used.