Iphoto which file am I using

Every time I try to use Iphoto I give up and end up using an old PC to organize my photos. Why is this program so difficult for such a simple task? I created a new folder on a separate hard drive for keeping photo's. But in Iphoto how do I know I am using it? Everytime there is an update it reverts to the old hard drive. I cannot right click or see which file I am using . This program has just been horrible from the start and isn't getting better. Why not allow us to drag and drop and organize our own photo's? So how do I know which file is being used?