We have seen adults confused between push and pull for their whole lives. This happens when the concept from childhood are weak. So, if you don’t want your kid to pulling a door that clearly says PUSH, you must make the difference crystal clear to them.
Before that, we need to learn some other concepts too, which is about force and energy. Whenever an object is moving we say that it is in motion and to put an object in motion some force needs to be applied to it. Force is the energy that enables the object to move. Now this force can be either push or pull. The key difference between push and pull is that we when we apply force on an object to move it away from ourselves we say that we are pushing it. However, when we apply force to move the object towards us we say that now we are pulling the object. The object will stay in its place unless or until an external force is applied to it which forces it to move and change its position.
After explaining the theory, you can use some real-life examples to further clear out the concept by pushing and pulling different things and asking the kid to identify the kind of force. This concept can save your kid from banging into many doors trying to push it when it says pull. So, keep it crystal clear.