Gameplan Task DocType

Gameplan
1

Hi

  1. How can I customize the GP Task doctype, Example I want to add a new feild which is currently not availble , I would like to add a float feild which calculates Task Days so that we know for how long a task has been running.

  2. I also checked that the in the GP Task doctype there is Start Date feild but that does not appear currently when i assign the task from the Gameplan application, what is the way to make it visible.