There are two options for your independent music in the music business: You can either try to be your own record label (and/or PR firm, music company, entertainment agent, etc.), or you can partner with others who will do the work for you if you pay them. Either way, you need to know who does what.
A Record label, PR firm, music manager, music publishing company, entertainment agency, music distribution firm, entertainment lawyer, music magazine, and most any other entity in the music industry are all part of a “mass media” wheel that generates airplay, publicity, gigs, CD and download sales.
All this is usually part of a record deal (from a record label), or, it can be used to get a record deal. Alternatively, you could decide just to keep as much of it in-house as possible, thus creating your own operation. This is a realistic option if you will be in the business for five or more years, and you are willing to work at least 30 hours a week at it, at a desk.
A real record company handles four basic areas of music marketing: Radio, PR (public relations), gigs, and retail. The radio portion is what these articles are about; radio is the most complicated part of the music industry and the most expensive part of the budget of a major record label.
If you hire an independent radio promoter, they can also help a little with PR, gigs, and retail provided the airplay campaign is large enough.
The PR (publicity) portion of the entertainment industry is obtained by hiring a PR firm (or PR person). A large record label has these people on staff, but will still sometimes hire out for more push. A smaller independent record label sometimes will just try to do its own publicity, maybe by just focusing on some local music reviewers. Big mass media music magazines, however, will be beyond what an independent music label can easily get.
The gig portion of your music marketing is obtained by partnering with an entertainment agency that books gigs for you (good gigs can get you some PR too), or by hiring a gig promotion person.
Small music labels will just try to book their own gigs since their gigs do not bring in enough money to interest agencies. Note that a booking agency for gigs is not the same as an entertainment agent that an actor would have.
The retail part of the music industry is split between brick-and-mortar stores, and download sites. As of 2013, about half of all music sales come from each one. A record company would hire a retail promoter, whereas a small independent record label would just call stores on their own.
Note that this is NOT the same thing as music distribution, which is simply a middleman between the record company and the music retail stores… they just take retail orders once the retail promotion person causes the sales to happen.
If you have no retail promotion person, you will have no brick-and-mortar sales, regardless of the radio that you have. Online sales require salespeople too, however, some small amounts of sales can occur without salespeople.