The Beginner Cardio Program consists of 3 runs per week: one or two easy (Zone 2) run, maybe one tempo (Zone 3) run, and one speed session per week. The kilometerage starts at 17.2km and builds to 24km.
All zone 2 runs should be ran at a comfortable pace. During those runs, feel free to walk, rest, or slow down. Don't worry about your pace; just focus on breathing calming and finishing the distance.
The tempo (Zone 3) runs should feel brisk but not super difficult. It should feel like your boxing: not easy but not out of breath.
The Speed Workouts on friday are meant to be the more difficult sessions. For all those workouts, aim to have a consistent time for all the repetitions. Best average is the fastest time you can maintain for every rep. Have 1-2 minutes of rest for the shorter distances - 800 or less - and 3 minutes for distances over 800.