Here you go, this one is good, its from an xterra forum but pretty much the same since the frontiers, xterra's and pathfinder share the same front suspension.
http://www.thenewx.org/forum/showthread.php?t=2497
this how to shows how to change your spring and the steps required to do so, but of course your just gonna use your stock spring and put a different shock on it, but same way to do it.