Playing ledger lines on the violin?

I dont understand how to play ledger lines on my violin. I mean do I go to another string? or do i move up(more to the bridge) on the string? also, how in the world is somebody supposed to play 32nd notes and 64th notes? isn't that impossible!!!!! i know its not impossible but how do you get your fingers to work that fast?!?!?!?!?!?!?!?!?!?!??!!??!?