The question everyone wants to know is, "How do I start adventure racing?"
The question isn't an easy one, but I'll give you some basic guidelines here:
1) Set a Goal. Identify a race you want to do is the starting point. Ideally you want to start with a short race, probably in the 2-6 hour range. Starting with a short race allows you to test the waters before committing a lot of time and money to something you don't even know if you like. Pick a race at least 6 months from the current date.
2) Find a team. Ask your friends, coworkers, or family members if they want to race with you. If you are lucky enough to live in a city with a local AR club, get involved! Clubs are a great way to not only find teammates, but to learn from the more experienced racers. Experienced racers will be able to give you valuable tips to make your first race a great day. Find someone you know that you will have fun with.
3) Start training. Before racing, you should be able to find out what disciplines the race involves. You may even be able to get approximate distances too. Gather that information and start training there. Work up to the miles or time you think you will do of each discipline during the race. If you have to bike for 10 miles, at some point in your training you should work up to this level. You should be able to work up to doing each discipline in one workout. For example, start with a run, then transition to the bike, and then to the boat. Doing all three disciplines in one workout will leave you with a good idea of what race day will be like.
4) Buy gear, use it. Get the gear you will race with and practice with it during your trainings. This includes food too! Know what works with gear and food during training so that come race day, nothing is new.
5) Have fun. Race day is about fun. While you are racing, enjoy the company, the outdoors, and the feeling of it all. You worked hard for your first race so enjoy it!