Before you start some serious triathlon training, you need to establish the basic principles and assess your own personal level of fitness as well as your strengths and weaknesses. Here are some general guidelines to get you started.
Whether you've moved up from one sport to three or have been sedentary up until now, you need to progress slowly with a new sport. Your joints, muscles and tendons will all take time to adjust. Over-strain your body with too much too soon and you may get injured and frustrated, just because you used to swim, cycle or run proficiently does not mean your body can still do it. Take small steps, not giant leaps. This may mean putting off training with fitter people until you've acquired some basic fitness.
Your advisers should draw on their experience and be in a position to offer useful training, nutrition and equipment tips based on sound principles. Your ability to filter advice and make it relevant to you is paramount. A good coach can guide you when you have problems and will it make it easier for you to get back on track. Your local triathlon club can advise you on how to go about finding a coach.
Triathlon requires more equipment than almost any other sport. You need the correct clothing and tools to train in three sports and eventually compete. Start with entry-level purchases rather than getting the best or being persuaded to buy something that's a waste of time and money. Apart from what you need to train and compete, less is more. You will have enough equipment to find, sort out and keep maintained without having unnecessary items.
It is important to build your foundations in all three sports slowly. This 'base' combines practice in the technical skills of swimming, biking and running with modest-effort endurance training. It gives you the skills to improve your efficiency of movement and the endurance to be able to complete race distances with ease. Having good stamina and skill enables you to add speed later - if needed - without your muscles or co-ordination breaking down.
Goals don't have to be permanent; instead, see them as tasks to complete, and break down your big targets into smaller, manageable chunks, it may be that your goal is to run twice this week as you did not run at all last week. You also need to get your bike serviced and find out the new pool timetable for laned sessions. Add these together and you've moved forwards. Remember that short-term tasks break down big goals, making them less formidable.
Please consult your doctor before beginning any type of training program.