Calf training is an often misunderstood part of vertical jump training. Yes training your calves is important as they are the main extensor muscles for the ankle, and therefore a key player in achieving a big vertical jump, but they also already get quite a lot of indirect training stimulus.
Realistically all direct calf training is generally either a strength exercise or a jumping exercise. Strength exercise can be done on a standing calf raise machine, or a seated calf raise machine, or standing up on a step holding some weights. It doesn't really matter that much but I like to do my calf training using single leg exercises over two leg versions. I just find it isolates the muscles better.
The other type of stimulus is jumping. Calf training focused jumping exercises involve little or no knee bend to reduce the role the quads etc play. The key variable here is intensity. Single leg drills are higher intensity than double leg drills. Calf training jumps for maximum height are harder than skipping rope drills. Both target the calves, just one is much harder than the other.
The skipping rope work is great as a warm up exercise for any style of training. It not only develops reactive strength, but also core strength and coordination.
Weighted calf work is best done using heavy loads for anywhere between 5-15 reps for strength. I like to do a 3 second isometric hold to build as much strength at that take off angle as possible.
I also like to incorporate calf raises in between sets of squats or deadlifts (or any exercises really) in the gym as those compound lifts tend to use the knee and hip extensors a lot more than the calves, so performing them in between won't impact too negatively.
Lastly the maximum height focused calf training jumps are ideal for building explosive and reactive strength, and again, can be performed pretty much anywhere.
Calf training for increased vertical jump height doesn't need to be overly complex. You can perform any variation of the above 3 exercises and get a pretty good calf training effect.