Experience Levels
Novice: You've done these 1-5 times with coaches watching and giving you feedback. You need reminders about where to put your feet, how far away to be from the bench, how low to go, you haven't tried it using weight yet.

Intermediate: You've done these 6-10 times with coaches watching and giving you feedback. You may need a reminder or two but know generally how to set up and have an idea of what weights you could do for certain amount of reps.

Well Practiced: You've done these 10+ times with coaches watching and giving you feedback. You know where to put your feet, how far way to be from the bench, what weights you can do for how many reps, how low to go.

Difficulty and Equipment
This is not an absolute scale, but in terms of progressing in ability here's how you should be progressing:

Unweighted, potentially holding onto something for balance. (Novice)
Holding 1 single dumbbell in the goblet position (Novice/Intermediate)
Holding 1 single dumbbell in the suitcase position (at your side with straight arms) (Novice/Intermediate/Well Practiced)
Holding 2 single dumbbells in the suitcase position (Intermediate/Well Practiced)
Barbell in the back rack or front rack positions (Well Practiced)

Progress in weights before moving onto another difficulty level. How much should you be able to do before moving on? That's not a black and white answer however a good guide is 3 sets, 12 reps per leg of that weight before moving up in weight or difficulty level.