Instant 100s are new instant games to compete against a larger pool of players with around 100 tables. Given you're playing against a bigger field, you stand to win more points.
You're dealt deals from a previous tournament and your scores are then compared against other competitors who played in that tournament. After each board, you get to know your final score for that board and your current rank in the tournament. Do well and you'll win ACBL Masterpoints®.
Click ACBL World then click on ACBL Instant Tournament then select the ACBL Instant 100 of your choice.
Each tournament is 12 boards long and you must complete all 12 boards to be included on the leaderboard. The time limit is 24 hours. If you're idle for a long time, you can continue your game progress as long as it's within the 24 hour limit.
Games are "Best Hand": you will always have as many or more HCP than the next best hand. It's also "Human Declares", meaning that when your robot partner wins the contract, you will play it.