Below your post you will see a small link labeled "delete." Only the original poster and the mods can see this link. Just click it. A box will pop up asking your for the reason for your deletion. Fill it out if you wish and then click "delete post" to confirm that you want to delete. Done. If your issue is with someone else's post that you think should be deleted, then in the same area as "delete," click on the link that says "report." Or, PM a mod directly.