This is a great way to combine upper and lower body work. The Lunge works quadriceps and hamstrings, whilst the Press will work the triceps, trapezius and shoulders. By pairing the two movements together you will have the added challenge of balance, causing your trapezius to work harder to stabilise your shoulders and your core to engage.
To begin with you will rack your weight (Kettlebell or Dumbbell) over your right shoulder. From here you should step forwards into a lunge with your left leg. Push your left leg back up and together, so you come back to standing. Then press the weight up to a straight arm before repeating the whole movement.
In order to make the movement more challenging you could press the weight up when in the lunge position rather than once standing.