When you see a number next to the same letter, the exercises are to be performed together in sequence. For example:
A1) Kang Squat
3111; 4-6reps; rest 60sec x 3
A2) GHD Hip Extension
3012; 6-8reps; rest 60sec x 3
This means to perform 4-6 reps of the Kang Squat at tempo, rest 60 seconds, then do 6-8 GHD hip extensions at tempo and rest another 60 seconds. Repeat this sequence two more times for a total of 3 sets.