When listing my first product to sell, why am I not getting the page to enter in vital info

I’m hoping someone can help me understand what I’m doing wrong or what is going on. When trying to add a product not sold on Amazon through seller central, for most product categories I select I get come to a screen where I have to enter in the standard info: Vital info, variations, offer and images.

However, for the specific product I am trying to sell (a computer keyboard), I get a different screen with different options: Supplier description (asking for contribution SKU), product identity, offer, product details, variation, etc. I also get a message saying:

When multiple sellers sell the same product through a single detail page, we combine and present the best product data to ensure customers get the best experience.

What’s the reason I’m not seeing the typical/standard information to fill in and am being asked for more information? I haven’t seen any Youtube videos covering this. I get that a computer keyboard is common, but so is a ball point pen and the pen category takes me to the standard screen.

Any help would be greatly appreciated!