Find the rack with your number and place your bike on the rack. Before you pick a place on the rack, find out from which direction you will be entering it from the swim and from which way you will leave on the bike and run legs. Once you figure out the best spot, put your bike there. Positioning of the bike can save crucial seconds. If there is someone at the race with you, you might ask them to watch your spot when you leave to warm-up.
People tend to move bikes around when unoccupied before the race.
Now is the time to setup your shoes, helmet and racebelt. Take the towel out and place it on the ground. Then place your helmet on the ground on your shoes or on your bike seat. Leave the chinstrap unfastened so it is easy to put on. If you are going to put on a race belt, put it next to your run shoes, so you remeber to grab it.