How do i make the player behind the solid object?

I'm trying to make an RPG game with construct 2 I want to make the player z behind the solid object

Make a family with all the objects that you need to manage Z order for.

Give the family a numeric variable to keep track of their Y position.

Every tick, set that variable to their Y position, then update family's Z order.

You can check on an 'every X seconds' interval or only when the character moves if you want to save on CPU usage