Sign up for a craigslist account (it's free) and simply read and follow the instructions on how to submit an add. I would suggest, if you don't already have one, obtaining a separate email address for your craigslist account, one that doesn't reveal any of your personal information. Also, if you are going to put your phone number on craigslist, get a disposable, cheap phone number. You can get one of these from phone.com for $5.12 per month. Use this number for craigslist ads and forward it to your phone number of choice. This way your personal phone number will never be revealed to anyone. Lastly, be very careful about craigslist. There are a lot of scams. Personally, I don't usually reply to emails, as they are often phishing scams. I got the best results when people telephoned me. I sold about 10 items last year on craigslist with great success.
Good luck to you!