Not really to do with trains, but this is an off topic channel so I'm gonna assume it's ok to ask... I apologize if it's too weird to ask. So... I've got some dumbbells, (weights you lift), but I'm not sure of a good way to lift them that doesn't burn off body/belly fat, but lets me bulk my arms up a bit, so they don't look like twigs.
You're best off using the dumbbells as one tool in a balanced workout, rather than simply lifting them as your workout. You also need to learn proper form, warming up and stretching, and choosing the right weight for the right moves (all very important for minimizing the risk of injury). There's plenty of good programs on DVD and YouTube. Some research will help you find something appropriate for your current age and plysical condition.