Nope, just respond to the ad as it is posted.
I have used craigslist a number of times, both for selling & buying.
It is easy & free. But, do not deal long distance where it seems TOO good to be true....there are scams out there too.
Reply to the ad, get a phone number etc. If your dealing with some distance,
ask the seller for pics to your email etc. Talk to the seller etc.
Good luck !!
Rob