How Do You Bulk Up?

Hey there I am about the same age and started doing this a year ago. The best thing to do is to stick to Cardio. Cardio is when you get your heart rate up. This can be done by going on bike runs (which have to be at a resonably quick, constant speed) Or a jog. This is all good for losing weight, bulking up and for your lower body strength. To bulk up your upper body you should get yourself some weights. All you need is a long bar and dumbbells. You should start out lifting low weight as your body will not be used to the change. There is alot of exercises you can do, some are found here : www.scoobysworkshop.com
This is a great site with great tips that I have used in the past. It will tell you all you need to know ;)