Whats great about this routine is you dont need a spotter and you only need one piece of equipmetn, a lat pulldown machine. Simply pick a weight you could do for 10 reps. Start by performing 10 reps of lat pulldowns with a very wide grip ( this will really hot your lats ). After completing the set rest just 15 seconds and then do another 10 reps this time with a narrow grip, hands should be about 8 inches apart ( this will put more focus on the mid back ). Once the narrow grip set is done rest a full 90 seconds and repeat from the start for 2-4 more sets.
Wide grip Lat Pulldown 10reps
REST 15 SEC
Narrow Grip Lat Pulldown 10 reps
REST 90 SECONDS AND REPEAT 2-4 TIMES.