What should i follow to develop admin side plugin

Hi,
In my project there is need a crud interface in admin / member login.

I have to attached a entity user wise as per following flow.

scope: tasks assigning to users.

- admin can select user and assign new task to specific users. ( one task for one user)

- then user login and able to modify the description and status of that task

- user should be able to child tasks to the main tasks.

- task will have three fields now
title, description, valid from, valid till, status.

what should i use here post-type, meta_options or ?

So, I have to develop myself, i need to better guidance , example etc.

-- only login members can see his tasks
-- admin can add/edit/delete/modify any task of any user.
-- also i need to create users tasks stats with chart etc.

what you suggest and how to go for...