hi , you need to log-in to admin panel then either you can turn off all the products which will disable their appearance in the front end of your store.And more information of adding the product follow the documentation
http://docs.abantecart.comIn other case if u just want to change the images u need to edit the product media tab where u have to unlink the old image add the new one and save the product refresh your front end and you will be happy looking the changes.
Changing logo Admin-System-Settings-and their you can change the logo and also fill your details for store .