source codes

I have had an invention idea for a phone and need some advise on what to do next. For example: Do I need the source code of the phone to place the software on it or do I simply need to unlock the phone?

A newbie to the site. Help is appreciated

depends what you mean, are you trying to load a game or as such software onto your phone? if so you can do it.. no need for unlocked or 'source code'