[Tutorial] how to make a block that changes model (or texture) depending on its variant

already to start when you have a block that varies they will change model depending on the cordinate

but beware it will not change model even if you replace it !

to start you must have two blocks (except for rotations) example block 1 and block 2

click on block 1 then on the bar (edit code selected of mod element) then you click on the JSON blockstate code

you copy this code

{
    "variants": {
        "": [
            { "model": "YourMod:block/block_1" },
            { "model": "YourMod:block/block_2" }
        ]
    }
}

If you want to add more block you add to block 2 a comma and then you add block 3 without comma
{"model": "yourmod:block/block_3"}

and done !

I will improve my tutorial in the coming days