I'll try and sum it up as simply as possible, because it's a pretty long winded topic. Firstly, in terms of Amazonian Curandismo using Ayahausca, the Curandero will have acquired a lot of knowledge and power from the plant spirits throught the isolated 'dietas', etc. These will be put to use in the healing ceremony. He will use the Ayahuasca to help diagnose illness, and then use a combination of Icaros(healing songs), Mapaccho smoke( jungle tobacco), and sometimes sucking, to remove the sickness.

The Curandero will also often prescribe suitable plant medicines to further assist the patient in recovery.

I seriously recommend further reading on this very fascinating subject. What i have said is the most basic of explanations, that of course does no justice whatsoever to these ancient yet living traditions in use today.

It's true to say that discussing a topic is much more constructive when one has a fair base idea of what say Curandismo is about. There exists many different types of Shamanism, but it's all similar in the way it works on a Spiritual level. Amazonian Curandismo is the most likely candidate considering the nature of this forum and the Entheogens in discussion.

I hope i have been able to provide a basic idea of what it involves, although further reading is highly recommended. Many good books out there.