I find that using cold water kept in the fridge speeds up the process.
Make Jelly using the boiled water as per packet directions, then add the cold water, and let cool before adding each layer.

Good question!

Let the first layer to set and leave the sencind to get to a cooler temp but still able to pour it

Let the first layer fully set. Then when it’s time for the second layer, let the mixture cool down to room temp before pouring overfirst layer. Repeat as necessary til you have all the layers you require

Cool the new layer in a measuring cup or jug in the fridge before pouring it onto the previous layers, using super cold water in the second step helps as well

I’ve always wondered this – great question!

Put it in the fridge for a longer time and then do the next layer

I cool the second layer of jelly before pouring it on top of the first layer so it isn’t hot and melts the first layer.