Cub scouts are divided by age/grade. During the year of your given strata, you can work on things to achieve the rank (get a patch to wear on your shirt) - or you don’t.
No matter your progress towards meeting the rank requirements, at the beginning of the next scouting year, you begin the next ‘class’.
Lions - Kindergarten
Tigers -1st Grade
Wolves - 2nd Grade
Bears - 3rd Grade
Junior Webelos - 4th Grade
Senior Webelos - 5th Grade
A den is generally 5-12 scouts. If you’ve got a lot of scouts of that age, you’ll have multiple dens.
In my experience, dens usually meet at their meeting place twice a month.
A den will go on an outing once a month.
All the dens associated with the Pack will then meet together once a month. So you’re getting together once a week for the school year.
Cross over into Boy Scouts, and suddenly the ranks become more achievement based. There’s a few time-gates built in- you have to be with the troop for a certain amount of events or timeframe before you can advance. In addition, you have to prove that you can plan a meal, tie a knot, splint an arm, etc. But you may have a 16 year old kid that’s still a tenderfoot scout, and a 13 year old scout that’s pushing into Star.
The first rank of scout is kind of new- this is just some basic rote memorization of boy scout oath, law, etc- prove that you kind of understand what scouting is about.
The next ranks through First Class are all about learning skills that you stereotypically associate with a Boy Scout- the knots, the first aid, the camping.
Then at Star through Eagle, the incubator shifts slightly, and the boys are now supposed to start using their learned skills to start taking charge of the troop. They’re the ones driving the troop and providing the leadership to the younger scouts. They have to earn some Merit Badges (which serve a purpose of diversifying your interests and skill set- do you want to learn about robotics, or prefer to do auto repair?) but at the heart of it, the last three are just a crucible for leadership. The famed Eagle Project is really just teaching scouts to organize a project involving people outside of themselves. Collect requirements from a user, determine resources that are needed to meet those goals, gather the resources of time, people, and materials, and then execute on the plan. Doesn’t matter if the project is built as designed, or a total failure- the Eagle rank is really just about the road of planning and executing. It’s just a mini Project Manager certification wrapped up in khaki, red, white, and blue.
I’m sure that’s more detail than you were hoping for.