Isometric Sprites

This might be a stupid question but I'm stuck and can't get passed it. I'm making a isometric game and I have my map built using tiles, I just followed this tutorial to build the map, http://ift.tt/1puY2p0. But now I don't know how to add character sprites. Do I have to add these sprites using tiles as well or do I just draw the the sprites into position of the screen. Any help would be much appreciated.