Certified GKH Gardening Expert
There are many ideas on how to prune orchids. All of mine are grown under a 750watt LED panel, and in a climate controlled area along with other tropicals to mimic its natural environment, I don't know if your area remains constant, or if it changes often, as this would affect how you would prune it. In my case where it is constant... You will only want to remove spent blooms, leaving the stalk intact, as they will flower again from this. If the climate is not stable, then I would recommend pruning the stem all the way back to focus on leaf growth, as it will already be slow due to constantly changing climate.
There are many different methods for many different needs, so here is an article with more information: https://www.gardeningknowhow.com/ornamental/flowers/orchids/how-to-prune-an-orchid.htm