Need help in organizing/mapping my data
You're half way there with this. I would say that the three types of people are 'Contact Types'. Groups and/or Tags can be used to break these down where relevant, for instance, tags might be used to identify who actively contributes to your org, and groups might be used for the people that you will be mailing newsletters to.

The rest are probably mostly custom fields, with the exception of the medium of introduction to your institute - this may be an activity (use activity types and/or custom fields to specify the information you want to capture) because this will make it easier to see how many new interactions you've had in any given time period.

Ultimately, though, CiviCRM is really flexible and there are other approaches to capture and report on the same information. If you give some thought now to the specifics of what you will report on, you may decide that there is a better approach.