Ideally, you want to start at the beginning of spring for the best chance at a successful propagation. Make sure that any wintery cold weather is behind you so that your cuttings are growing in warmer brighter months. The whole process can be a little slower than other houseplants as their roots will take some time to mature so make sure you don’t leave it too late as they will struggle to grow once autumn arrives.
Starting in autumn or winter will mean that your cuttings will be trying to develop roots and new leaves at a time where the plant is usually dormant. This means you won’t really see much happening at all and the risk of leaf and root rot is a lot higher.