Welcome to the Nexus! 

If you haven't yet, I deeply suggest you read the health and safety section and the FAQ, there's worlds of information directly in those two sections or linked there which could be useful/interesting.

Regarding "traditional brazillian rainforest", not to nitpick but ayahuasca is not just from the brazillian amazon but also present in other countries in south america such as peru, ecuador, etc..   Also, it's hard to say what the "traditional way" is because it is dynamic, the traditions change, and since there is no written record in the amazon its next to impossible to know how it was in the past.  It's very possible that the earlier uses were just of banisteriopsis caapi drank in cold infusion, without DMT admixture, which is far from how its used by many indigenous people and groups nowadays.  

In any case, if you want to learn how to brew ayahuasca, check the FAQ (the part on brewing and on dosages), and this will lead you to more than enough info

Do you have any experience with any psychedelic?