Conditional Visibility Based On A Variant

I’ve been spending the past few hours trying to understand how to make an element only visible if a certain variant is selected. I’ve tried to use the SKU but it doesn’t seem to work, I can’t even get the main image to change based on the variant selected. I know it sounds really basic but I just can’t figure it out. I haven’t found anything about this simple thing online too, which only frustrates me even more.
I’d greatly appreciate any help.