Below is the link to the provider ad posting guidelines. You can actually find that, and a lot of other good information in the Self Help Center (to which a link is located at the top of every discussion board page near the red and white life preserver)
You can also find lots of help on the newbie board. There are a lot of helpful people there to answer all sorts of questions, and if you just read a few pages there you can learn a lot since the same questions tend to get answered over and over.

For ads, read the info in the link I provided, but in summary, you can place an ad once every 7 days on your home regional ad board. You can also place ads on other regional ad boards if you are visiting that city but for visiting ads you must post the dates in the subject line. All ads on TER must have a link back to either your website, your TER profile, or profile on P411 or other verification site, or your ad on an ad mall.

Good luc