As far as most numbers rackets go,the Mob is only involved at the upper levels such as operating the "banks" from which winners are paid,losing wagers are deposited,and the "juice" payments to the cops and politicians are made.

On a day to day street level,the people who take the bets and collect the money can literally be anyone. A guy who works at a large warehouse might take bets from co-workers. Bartenders,teachers,barbers, might pick up some action from their circles as well.

Most numbers writers(the people who take bets)are everyday folks who have a connection to someone and are picking up a nice side income. Anybody who takes numbers action will turn their "play" into someone up the chain.That person then kicks up the money to another person up the ladder.

Generally speaking,the organizational chart is as follows:
Made Guy,usually a Capo
Made Guy (Soldier)
Associate
Workers
In a given neighborhood,the workers turn their money in to an associate who May supervise 10 or 20 writers.
The associate then turns in to a higher level associate,or a Made Guy who is responsible for multiple neighborhoods or areas,
The Made Guy then turns in to his Capo who may have 8 or 10 (or more)Made Guys kicking up from their areas.
Of course the Capo then kicks up to the Boss.
This is a very general outline,but pretty much covers the basics.

There is no central office or location involved,and at each step,the money and betting slips change hands at bars,restaurants,car washes,parking lots,etc.

The commission structure for the street level writers is usually from 20-30 percent of all the action they take. This is a good deal for the higher ups,since a lot of people use their commissions to play their own numbers.Of course they lose most of it back to the operators.

Hopefully,I helped you out a little,but if you have any more questions,fire away.There are tons of fellow posters who know all about this stuff.