Can you describe how to do an intermediate "sample" VWC session with the 12kg?
Anna, there isn't really a representative sample session with a given bell. You have to take the cadence test to figure out what bell and cadence is appropriate for you.
Kenneth Jay has laid out a couple of versions of the cadence test. There's a six minute version:
1st minute: 10 reps left arm
2nd minute: 12 reps right arm
3rd minute 15 reps left arm
4th minute: 17 reps right arm
5th minute: 18 reps left arm
6th minute: all out effort
And a five minute version:
Minute 1: 10 reps, 1 rep/6 seconds
Minute 2: 14 reps, 1 rep/4.2 seconds
Minute 3: 18 reps, 1 rep/3.3 seconds
Minute 4: 22 reps, 1 rep/2.7 seconds
Minute 5: all out
The exact number of reps is not as important as ramping up over several minutes before the final minute (which is the actual test minute). A close enough approximation that is easier to time is:
Minute 1: 10 reps, 1 rep/6 seconds (snatch at :00, :06, :12..)
Minute 2: 12 reps, 1 rep/5 seconds (snatch at :00, :05, :10..)
Minute 3: 15 reps, 1 rep/4 seconds (snatch at :00, :04, :08..)
Minute 4: 20 reps, 1 rep/3 seconds (snatch at :00, :03, :06..)
Minute 5: all out
Snatch steadily for each minute, pausing in the lockout; don't do the reps quicker and then rest for the remaining time.
The all out number in the last minute is the one you base your cadence on. Divide that number by 4 for the 15:15 protocol and round up if you are above a whole number (so 7.1 rounds up to 8). The sweet spot for a given bell is 7 or 8. 9 is doable, but very rushed (and I believe 6 is also acceptable, although it seems very slow to me). So if you can do 33 or more in the final minute of the test, the bell is probably too light. If you can't get more than 24, the bell is too heavy.
Since 7-8 is the sweet spot, you COULD just pick one of those numbers as your cadence, but you wouldn't know if 12kg is the appropriate bell size or whether you should go heavier.
Once you have your cadence, just set a timer to beep every 15 seconds, and go to it, alternating work and rest intervals (obviously) and changing arms each work set, just like typical A+A training.
The goal is to work up to 80 sets at a given level, although I believe KJ originally suggested 50 and then increased it to 80 later on.