Take a total of 10 min, spend the first 3-5 minutes warming up
Then go for max unbroken set of Double unders.
Don't have them. No worries. Spend the 10 minutes, working on arm motion, wrist motion, (Speed Balls), Beaded ropes. If you have a few DU already, that's awesome, spend minutes 5-10 doing an EMOM style set of DU. Spend :30 seconds of work with :30 seconds of rest.