managing products

Hi,

Maybe I'm overlooking something, but I can't find any clear documentation on how to manage or setup the products for a shop. When I create a new product in the backend, I can fill in the dimensions. Is there any way to add more? I tried the charactaristics, but that is not working for me.
I need to create a list of some specs for each product, like dimensions, height, color, etc. If I use the charactaristics it will show a list with values to choose from. But I have, let's say, product A only available in red and product B only available in blue.
How do I do this?

I'm not sure if it's clear what I need. Just a list so customers can see what the specs of my product are.

And I was also wondering how I can change the layout of the product page? When I add a picture, it only shows the thumbnail in the product details? In the configuration I have set the image dimensions to 450x360 px but that is not used in a product page?

It would be great if I can find anything on how to get started with the products. The rest of the documentation is very helpfull, but I'm really missing this (or maybe I just can't find it )

Thanks a lot.

Oh, I see I did miss something... found how to add custom fields.

Still wondering about the size of the product image on a product page, though.

Thanks a lot, it worked!