I’ve been doing kettlebells for many many years now. I first started back when I lived in Moscow, this was very common strength and conditioning. My main advice would be to start with a comfortable weight and get used to doing the movement. Once you get more confident and find that the weight of the kettlebells are easy to do you can move onto the next weight up. But don’t make the mistake of going too heavy, its not about that. You want to gain good stamina first, this will help you when you do start lifting heavier weights.
Here is a couple of photos of myself in action along with a video from a while back. Many more videos on my youtube channels.