If you can't afford a kettle ball you are better off, you can do everything with barbell, and here is an example. As with all of our movement corrections, DO THEM, FEEL THEM, THEY MAKE A DIFFERENCE you can feel.
+ Firmly holding one side of a barbell, swing the load overhead, do not let go, you gym neighbor will not like you if that weight flies around.
+ Feet are slightly turned out and knees are facing the direction you knees are facing, knees should not dive in AT ALL, they remain over the feet.
+ Inhale down, exhale over head. Keep shoulders down on back, no shoulder earrings!!
2-4 sets 10-20 reps (depending on load)
Start with a 15 lb weight until you get the swing of it, then move on, most folks do not need to go over 30 lbs, if you do, do not swing over the head, just up to chin and keep your abs full of medium pressure, and keep breathing.