This guide will let you know how to make Hidden Stairs in the Minecraft game.
In order to make Hidden Stairs, you have to place pitons diagonally upward as shown in the image below.
After this place polished andesite blocks on the right side of the pistons and put redstone dust on them.
The next thing you need to do is to place polished andesite stairs on the right side of the pistons. Add one layer of stairs at their top in the same as shown in the following image.
Then fill the gap on the stairs by placing polished andesite blocks. Also place these blocks in the empty area under the stairs.
Now you have to place polished andesite blocks in front of the stairs and use redstone dust on it.
Add a lever on the right side of the wall. Pull the lever down and the pistons will push the hidden stairs forward.