Adding field in Category table and in admin area

[funksachin]

Hi,

I am new to Zen Cart and trying to setup a online retail store.
I have been able to change the feel and look of zencart as I want but I am facing issue while displaying the categories.
I would like to show two types of category on main page.
Some categories should come under "Current Sales" and other ones under "coming soon".
I think for this I need to add an extra field in category like "Starting Date". I should be able to add this starting date from Admin Area "Catalog->Categories/Product" and then based on this field each category should come under either "current sales" or "coming soon" on main page.
Could anyone help me in letting me which files to change ?
I think I should be able to handle the changes myself (although my knowledge in this field is limited) but I am not able to find from where to start.

Addition Info:
My zencart version is 1.3.8a and I have no add ons installed.
Thanks & Regards,
Sachin

[funksachin]

Could somebody at least let me know how to add "Start Date" input text form while adding new category from Admin panel...