Minecraft secret passage?

I'm trying to make a 2x2 secret entrance but it doesn't work.

I play in 1.16, can someone send me a video on how to build a 2x2 secret entrance in 1.16?

For a secret passage in the wall

For a secret passage in the ground

So the first design is not very secret, the door should already be flush.

What you are looking for is called Jeb Door.

Here's a guide