I am trying to organize my thousands of photo in Ipad. There are thousand of apps
for ipad but could not find anything. I don'r even know where my harddrrive is, please help.
You cannot organize an ipad like a PC - at least not from the iPad itself. There are PC programs like DiskAid that will allow you to access your iPad in an explorer like manner, but be wary of trying to change the folder structure. You may cause the OS to 'not see' the pictures anymore.
For photo management, Tex's suggestion is right on. The alternative could be PhotoManagerPro which I like a lot.
However, there is nothing on iPad that is truely Explorer-like. I've tried FileExplorer which fairly close but still no cigar since it cannot associate any external application other than its native ones. It's the natural limiation of iOS and I don't think there is a way to get around it. So there will be a lot of reinvented wheels and wasted resources due to this design nature.