Mirror isn't working for me

Hello,

I am new to blender, and trying to work through the Essential Blender book.

the problem is i have a square that i’m trying to mirror. The area is outlined in pink, and i press ‘Add Modifier’.

Nothing happens, but the book says it should mirror the square.

Any help is appreciated.

Hi,

Try moving the vertices around and see what happens. Chances are, your square is positioned halfway across the axis of the mirror, so your reflected vertices are positioned right on top of the vertices at the other side of the mirror.

dear cellis! welcome to blender world!
the mirror modifier makes a exact copy of your mesh and mirror it from the center of your object. because you add a modifier to the default cub , which its center is exactly in the center of cube , mirrored part drops in the same place as the cube is.
you can see the mirrored part by doing following steps:
1.go to edit mode(press TAB)
2.go front view(press numpad 1)
3.select all vertexes(press A)
4.press G for move and Hold ctrl , then move one square to right.
now you can see the mirrored part.