Firefox Portable : Ebay Stealth tool?

I have been hearing a lot about using Firefox portable to make profiles instead of user profiles on your computer. Can anyone explain how to make a second profile or link me to the article that has the best instructions (I've read several, not sure what works)?

Each Firefox portable install folder can be used for an ebay + PayPal account.

What you need to make absolute sure is that your adobe flash settings are disabled (google disable flash for eBay).

Usually if you disable flash settings on 1 firefox portable installation, the future installs will also have it disabled