Question about variations and creating them best practices: without losing reviews, etc.

Let's say I have product A. It's a successful product with a lot of reviews and it sells well.

I have different styles of that product (product B, C, etc) that are all separate listings. They underperform Product A quite substantially.

At the time I created it, variations were not allowed for that category (which is why I made separate products for them), but now it looks like the option is available.

I'd like to set up variations so customers can see the different options in one listing (I think that this is that main reason the other products don't sell well - lack of visibility).

What is the best way to do this so I do not lose the reviews and high ranking & everything from Product A? I'm worried that if I create a new product that is a parent, I'm going to lose all the juice from my product A.

Can anyone explain how this works, and how to do it properly so I retain the success of product A, but can list variations of this product?

I don't want to screw up and not be able to un-do a mistake, since there are so many things with Amazon that are not reversible!