I've never done this myself, only watched the guys do it, I'll try to explain the best I can.
Level your path area making sure that it is even.
Lay out your boundary using lawn timbers or 2x4 planks of wood.
Add your gravel and tada!
This page has an easy step by step guide with photos on how to lay a gravel path: http://www.thisoldhouse.com/toh/how-to/intro/0,,20048448,00.html"">http://www.thisoldhouse.com/toh/how-to/intro/0,,20048448,00.html">http://www.thisoldhouse.com/toh/how-to/intro/0,,20048448,00.html">http://www.thisoldhouse.com/toh/how-to/intro/0,,20048448,00.html