New actionable page in Categories

running v1.3.9 on Localhost with Win7 . XAMPP

Newbie here. Trying out Zen CArt and Magento..

My HTML site https://www.merlinmounts.co.uk has a Custom calculator in the Navigation panel (left) Similar to Zen Categories listing.

How can I make a new page in the Categories so that I can add the HTML coding and the PHP lookup.

I do not want to use EZ pages as they are not represented in the Category listing.

Seems such a simple request, Yet very hard to find a definitive answer.

Install Categories Dressing from Free Addons, and create "headings" for the first category that contain links to your calculator pages. See the readme in the download package for more instructions. You can use ez-pages or define pages for these calculator pages.
The "heading" links can be styled to look just like your category links.

Thanks gjh42 for the reply.
My understanding is that EZ pages are allocated to the 'information; sidebox.
I do not want this. I want it in the main 'category' sidebox.
So that when I click on it, it will then call 'Custom page' from wherever it resides- (That bit I have not come to yet).
The HTML coding is already as you see from my present web site.

I am to understand that a new page can be made that can be actioned from the main Nav Bar. I say that because a number of people are quite willing to charge me upwards of £500 to do it for me.
I would like to figure it out myself - or at least have a go.

EZ-Pages can have links in the Important Links sidebox, but they can also be linked to from anywhere else you desire by adding the appropriate link code to the correct file.

Categories Dressing allows you to create these links in the Categories sidebox.

Thank you gjh42.
I will have a look at that over the coming days.
If I struggle then I will be back