Your weights will depend on your ability to successfully complete sets working your way up from low weight to high weight.
For example,
I start with 5 lb weights on my first set of 12 to perform one arm dumbbell rows. My second set I go to 8 lb weights for 12 reps. My third set is 8 lb weights for 10 reps. Then, I finish my fourth set with 10 lb weights for 10 reps.
Sometimes, depending on the exercise I can't complete the fourth set with the weight I've selected.
Ignore my reps because they are smaller than what you posted, but when I first began my FT program I was also given the same target reps as you.