I think the term "mass slaughtering" is extremely out of place
Of course it is out of place, but I'm sure you saw the tongue-in-cheek.
BTW I was not referring to you, but to the industry of mass-produced mallsai.
They are sold per sea-container full. Monthly. By multiple nurseries.
You think you'll only kill 2? I think most bonsaiists have lost far more than that.
Learning to take care of trees indeed doesn't take months. Growing bonsai however is a lifetime study (OK, that may be exaggerated too, but what I mean is: even if you're an expert, there's always something new to learn. I have been trying to grow bonsai for many years, and I consider myself an amateur, not anything close to an expert).
One thing may not be clear - and that's my fault for not writing it - I do not advise you to not take care of your little juniper. It's a live plant, keep it alive and healthy. Maybe in a far future...
Just remember it's a small, fragile plant, no good material to practice on. Resist the urge to prune and wire it; you WILL kill it. Just let it grow and get bigger and stronger.
When you see it's doing well - the color stays fresh and green, you see new buds, branches start growing, you may want to consider trying to do your first steps. These would be minimal steps, it's still a small plant.
BTW could you give us a close up of the base of the tree and the trunk?