Move model by pressing the button

Hi. I began to study plugins, and faced with the problem. There is a lesson model_pish - http://gazebosim.org/tutorials?tut=plugins_model&cat=write_plugin. I wanted to change it up a bit, but do not understand how to do it. I wanted to make sure that the model is moved only to a certain place with the push of a button. In the next lesson, there is something similar http://gazebosim.org/tutorials?tut=elevators&cat=plugins, but there is no description of how it works. Please, if you do something lift excess, tell me how to implement this?

namespace gazebo
{ double x,z,y;
  class ModelPush : public ModelPlugin
  {
    public: void Load(physics::ModelPtr _parent, sdf::ElementPtr /*_sdf*/)
    {

      this->model = _parent;

      this->updateConnection = event::Events::ConnectWorldUpdateBegin(
          boost::bind(&ModelPush::OnUpdate, this, _1));
    }

    public: void OnUpdate(const common::UpdateInfo & /*_info*/)
    {
          while(model.getWorldPose().pose.x != x1)
              model.setVelocity(math::Vector3(1,0,0));
          while(model.getWorldPose().pos.y != y1)
              model.setVelocity(math::Vector3(0,1,0));
          while(model.getWorldPose().pose.z != z1)
              model.setVelocity(math::Vector3(0,0,1));
    }

    private: physics::ModelPtr model;

    private: event::ConnectionPtr updateConnection;
  };
  GZ_REGISTER_MODEL_PLUGIN(ModelPush)
}