For the medicine ball complex, you get as many reps as possible in the given time frame (weeks 1 and 2, 30 seconds, week 3, 45 seconds, week 4 60 seconds). For the upper body complex, you do the ropes for 30 seconds, the bodyweight exercises as many reps as possible until near-failure. (2 sets of everything the first week, 3 sets weeks 2 and 3 ,4 sets week 4).
For the explosive complex, it's just as many reps as possible in 30 seconds. 2 sets the first week, 3 sets in week 2, 4 sets in week 3.
I'd go with either dumbbell deads/squats (holding a dumbbell in each hand, like a trap bar), sumo deadlifts, or one-dumbbell deadlifts kinda like this (if the gym has heavy enough bells):