How to create new flow using Apache Nifi

There is only one top-level canvas, but you can construct as many logical flows as you like. Typically to organize things process groups are used, so the top-level canvas can have several process groups each representing a logical flow, but not necessarily connected to each other.

In the current version of NiFi users have roles, so if a user is a data flow manager they can see and change any part of the flow, and if they are a monitor role they have read only access. In a future release being worked on right now this will change to more fine grained access control per component. In the model, if there were two process groups on the root canvas, you could give one set of users access to only process group 1 and another set of users access to only process group 2.