The process is to create an armature out of rebar, then cover it with lathing and wire mesh, and stucco thin layers of a sand/cement mix. Additives are used to give the concrete different added benefits, like quick or slow curing times, added strength or water proofing. As far as concrete is concerned, ferro-cement is one of the most versatile methods available.
Your ferrocement project wants to be anchored to metal that you can cover in concrete. If making a wall, make sure that your foundation has some rebars sticking up out of it every couple of feet that you can tie the wall’s frame to. If making a roof, make sure your walls have exposed rebar you can tie to. And so on. This way, your building gets tied together at its basic level.
And that’s it. It takes a little practise, but once you get going, it is surprising how fast you can get a large area done. Be aware that the hardest stucco to do is overhead (like the underside of a ceiling). If you can avoid this in your design, it will save you a lot of shoulder and neck ache. Once you’re a little more experienced, it won’t be so bad, and adding acrylic to your mix makes it much easier (as it is stickier).
Ferro cement is a form of building that lets your imagination run wild.