The Advertising Sales Department: Sales Assistants
Depending on the size of your newspaper, you might also find people in your department who will help you process the paperwork called sales assistants. They most likely will have an answer to any question you might have about the products you will be selling, the procedures to get ads in the newspaper, rates and just about anything else you'll need to know. Even if there aren't sales assistants in your department, there will be someone besides the salespeople and managers who knows about all these things. I'd suggest you find this person and make them an ally.

Summary
And that's pretty much the overview of the newspapers. Again, if your newspaper has no formal program where you sit with the various departments to see what they do, and if you find yourself with free time and nothing to do, you might want to ask your manager if you can spend some time in these departments observing them. At the very least, spend a little time sitting with the artists, the person who inputs the forms you'll eventually fill out, and the credit and billing people. And most importantly, ask a fellow salesperson to let you observe them at their desk.