How to Advertise on Craigslist. Part of the series: Internet Guide. Post an advertisement on Craigslist by setting up an account, selecting the “Post to Classifieds” option, choosing the category of the listing, such as “For Sale” or “Job Offered,” and filling out the listing information. Set up an ad on Craigslist to post a job listing or sell an item by following the easy steps in this free video on Internet commerce from a Web site professional.