In Blender, a boolean is implemented as a modifier. You can reach the modifier stack by going to the wrench tab in the properties panel. In the modifier stack, press add modifier and choose the boolean modifier. You will notice that the modifiers name is red.

Why does Boolean not work in blender?

If a boolean doesn't work it's probably because something in your geometry isn't making sense (even if it looks and renders fine). Last time your issue was caused by inverted normals. This time it was caused by doubled-up verts.

How do you fix Boolean in blender?

To solve most Boolean problems, we can move the object a little in any direction. Also, sometimes you may have multiple meshes in the same object cutting into a base mesh. Separating these and making sure that scale is applied and having normals facing outwards is a good troubleshooting start.