Nuxeo Bundles roles

Question

I'm new to Nuxeo plateforme and i want to know what is the role of every bundle. in another way, how to know the the Java class of a specific object to modify or where put my functions?

Answer 1

what is the role of every bundle

The Nuxeo Platform Explorer is one preferred way to explore the bundles.

a specific object to modify or where put my functions

Your two other questions are not precise enough or highlight a lack of understanding of the Nuxeo framework.
Have you read the Nuxeo documentation or gave a try to Nuxeo University ? You will find there a lot of tutorials, how-tos, developer tooling, courses, etc.