on top right of page is "start discussion" that opens a new window.
then be sure to hit the little arrow in the "no prefix" box and mark the advert "for sale"
then give it a good title and write the advert.
Remember to give your car's location in the advert as people like to know how far they need to travel!....the USA is a big place!
add photos from your computor, by clicking on the 'paperclip' icon.