For some homework read through the information in this thread about structure and placement in the pond. There is a lot to see and read. It should answer most of your questions. New questions just come back and ask. We will be glad to provide some opinions.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92463#Post92463


aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management