With a running clock:

At 0:00 & 14:00
6 min AMRAP:
400 m run
in remaining time:
Box Step-ups 61/51 cm for reps

At 7:00 & 21:00
6 min AMRAP:
4 min Walking Lunges for reps
in remaining time:
Double-under → Single-unders for reps

divide the SU reps with 3 for result

Box Step-Up:
Alternating or Sets
You've got a few options with the stepup, you can do sets on each leg, and then switch, or alternate for every step. The first option will work more stamina, as it requires consistent contractions one after the other on the same side. The second option, alternating, will balance out the load, and give you better access to your breathing. Regardless of what you choose, be sure to balance out the sides.

Double-unders:
Timing
Timing is crucial for double-under, and along with the “whisking the egg” cue for wrists, there is also the coordination of jump timing. By focusing on when you jump, you can lower the necessity to jump high. Think about slowing down a little bit, and focus on jumping right as the rope is coming around and in front of you, close to your feet. This will allow for less energy to be spent on the jump each rep and that gained efficiency will add up.

We consider this system Vp(v) and if you imagine the way it will feel (primarily breathing) you’ll see why. You’re goal is to maximizing your AMRAP sets, keep that in mind on the run and lunges and don’t go out at a suicide pace. Focus on your breath from the start. If you can keep your breathing consistent your perceived effort will lessen. Get into a rhythm on the box Stepups… Box Stepups were chosen specifically for the fluidity and rhythm allowing you to maintain a consistent and smooth pace. While some may thinking “why not box jumps” the reason is because of the difference in the nature of the movement. We’re looking for consistent, smooth, high breathing, and the box stepup does this better. Work through the row and the bike at a high steady pace so that you can get right into the box step-ups and double-unders. Try to keep your AMRAP scores as tight as possible, don’t blow it all on the first round.

You’ll be setting up a clock, and letting it run. 6 min, with a 1 min rest. Pace accordingly!
You’re looking at 27 minutes of total clock time,