User, Account and Access Management

Hi, I have gone through the documents and available APIs. But confused with the actual modelling. 

There are accounts, and user can be a part of account. Whether there can be users without associating with any accounts? 

There are groups, organizations, RBAC Roles. Whether all these can be assigned and revoked from a particular user or is it possible to manage at account level. 

I am confused with the entire organization structure and how access can be controlled in Automox. Could you please check and share some detail around it. I want to know how to manage users and accounts, and also wants to know how to manage the accesses.

Thanks.