Hello and welcome to the forums
We have a lot of tutorials available in the MB3D section of the forum :
http://www.fractalforums.com/index.php?board=225.0But you'll find them scattered around elsewhere as well.
Precise placement of textures is not always possible, but there are settings to offset your image maps and also to scale them in the Lighting window, so I'd suggest playing around with those.
Fractal Art rarely is about making an image with a pre-determined idea in your head. It's more about finding the order in chaos and discovering nice stuff that is already there just waiting to be found.
Hopefully the tutorials we have here will help point you in the right direction.
There are also many tutorials off site on places like youtube and deviant art.
Good luck exploring and have fun!