Minecraft bug what can I do?

I want to build a Minecraft farm like in this video:

But this player builds trap doors on trap doors and can place them under a block and on blocks. I play on the same Minecraft version but it does not work for me but I'm in need of help

Hi you've already tried the trap doors to the carpets to place

No, what do you mean?

Take the trapdoor in your hand look at the carpet and press rightclick

You have to press Shift (the sneak button) while you place the trap door on the other trap door with a right click.

Func. Not