MITCHELL consists of 2 parts that you should complete one after another.
Part a) is a pure strength circuit that includes bench press and pull ups. Start with 12 Bench Press followed by 12 Pull Ups, and reduce the reps by 2 each round. While you decrease in reps, you should increase the weight for Bench Press each round.
Pick a weight that allows you to complete all reps unbroken with good form. There should be little to no rest between transitions. After each round, rest for 2-3 minutes.
Part b) is a 20 minute AMRAP that includes Ski Erg, Sled Push, and Rowing. For the Sled, pick a weight that allows you to push the entire distance without resting.
Scaling: You can scale MITCHELL by decreasing the reps of part a) by half and by doing Ring Rows instead of Pull Ups for part b), decrease from 20 to 10 minutes.