You can use the squat press machine (adjust weight if needed), standing with dumbbells, or an actual calf press machine. Go slow & controlled, especially on the return motion. Use mind muscle connection to really squeeze your calves the whole time!

Weight Recommendations:

Beginner: 10-15 lbs on each side
Intermediate: 20-45lb plates on each side
Advanced: 50-90+ lb plates on each side