Answer: Well it´s actually easier than you imagine.
Explanation: It´s just a short and weak (unnstressed) syllable, followed by a contrapart: a long and strong (stressed) syllable.
Take a moment to consider and think about how useful the application of this concept could be. It basically marks the rhtyhm of how poetry works. If it´s a walk through the park, jogging in the stadium or running for your life.