The practice of each of the Four Thoughts that Turn the Mind involves contemplation—for example on the preciousness of human existence—and a meditation on the same. The first, contemplation, would then involve reflection on the nature of the preciousness of human existence. We can then shift to meditation when we reach a point in our contemplation practice where we feel fatigued and unable to reflect anymore. At this point we just abide in a state of mental restfulness, not thinking about anything. We do not follow after thoughts of the past, the future, or the present; we simply abide in this state. When distracting thoughts emerge, which they inevitably will after a few minutes, we then return to our contemplation on the content of the four thoughts. We can do this with each of the four thoughts so that each practice session of the four thoughts has a contemplative and meditative element.
Depicted from "Guide to the Four Preliminary Practices 3 - Part 37" April, 2015, Vancouver, Canada