Kettlebells come in numerous weight amounts. Choose a weight that is challenging but not too heavy. The weight should be heavy enough to be challenging but not too heavy to use poor form and risk injuring yourself. Kettlebell training is unlike any other, as it requires power, strength, mobility, stability, cardiovascular fitness and good endurance. These are dynamic exercises that allow the body to move fluidly and use different muscles at the same time.
One of the basic exercises is to put the kettlebell between your legs while bending and then explosively swing the bell up to shoulder level. This exercise is using your quadriceps in your legs but also builds your core muscles and arm and shoulder muscles. By doing a set or two of this exercise you are also getting a cardiovascular workout. You can vary the exercises and be able to focus the exercise on whatever muscles you want. Below is a video I found to help demonstrate the many things you can do with kettlebells
The kettlebell is an excellent way to workout because it builds strength, stamina and burns fat. It is a dynamic exercise that works multiple muscles at the same time. Many gyms have classes you can go to that use kettlebells. You should check them out and see how you like them.