If you decide to weight train, then go to your local gym and have an introductory lesson so you get to know the apparatus first, he will also show you how to lift safely and give you a guide line where to start, It i much easier to train with a Friend as you can work together and have some friendly banter. It is also better to have someone you know and who will help you lift the heavier weights, start with small weights and More reps then gradually work up to the heavier weights and reduce the amount of reps, train parts of the body on different days and always make sure you don't over do it because there is always another day. Another important thing in weight training is you warm up, have a 10 min run or bike ride before you start to reduce the chances of pulled muscles.