A bump is like a kid going into the gym, lacing up the gloves for the first time, and sparring for a round or two. Just to see if he's into it.
With the dogs, that means seeing if the young dog will defend himself, and (if so) whether he appears to truly LIKE the contact or not.
If so, he can begin schooling on the next roll. If not, then pick him up and give him more time.

Schooling is taking the (now) started dog and putting him with different opponents, with different styles, one every couple of months, to "educate" him as to what he needs to do with varying opponents. A leg dog one time. A chest dog another time, A stifle dog a few months later. A head dog after that. Etc. This will take about 1 year (between ages 2 and 3), to recover from each roll and then move on to another opponent a couple months later, all the while they're maturing into a full-fledged adult.

By the time this schooling year passes, and 3-6 different schooling rolls are under his belt, your dog should have shown you if he has the ability to adapt to each style and win ... or not.

After he is schooled, either game test him or match him for real.

Jack

PS: Not every dog will fit this exact time table, but this is a general rule.