I am a total newbie to this I have a site allready on hostgator but i want it replaced with the 68 classifieds stuff If i pay for installation will they be able to do this and get it running so i can edit it for public use
That depends on what you mean by, "...replaced with the 68 classifieds stuff" exactly. Installation means, uploading the software files, configuring it to use the database and setting up one administration user. If you install the NEW software files (the 68 classifieds) over the same directory/folder that your current website (files) are by replacing and deleting the old files than the old site and files will no longer show or work. However, if you mean you have an existing website and you want the new 68 classifieds to look like your existing site (web template) and/or your existing site already has classifieds there (existing data and content) and you want to have those existing classified ad listings to be in the new 68 classifieds, then that would not be included.