Putting batteries together

Here is a new guy question. I am about to invest in some IB batteries and have never put a pack together. I have the deans connectors, wire, connectors and a soldering iron. WHat is the best way to put together a 6 cell pack for a E-Maxx with plans to upgrade to 7. Do the wires have to be the same length? Anyone with pictures? Thanks for all of your help.