Block variants

Hi, I'm working on Mcreator 2021.1 since new versions of Mcreator have no support for minecraft 1.12.2, my problems is that I can't  make variants of a block.

Here is my code:

{
    "variants": {
        "": [
            { "model": "nefrandomstuff:block/stones_0" },
            { "model": "nefrandomstuff:block/stones_1" },
            { "model": "nefrandomstuff:block/stones_2" }
        ]
    }
}

And they don't work, I've done some block variants before, and it worked just fine in another versions of Mcreator, Is another syntax for 1.12.2?

I know my english sucks.