Give me $250K and i'll consult you in the difference between DSL and Cable.
Since your ambition to be the next big white-label reseller, for $50K more I'll create a botnet for you to spam the forums about how great you are. This will attract attention to your next great big reselling company.
I was there in the early days and it was mostly a matter of acquiring a few modems, landlines, and a T1. Not anymore, and given you're asking this question here, Shrug isn't completely off the mark. There isn't a "Setting up a TPIA FAQ" available.
I think you'd be better off considering a TPIA reseller program such as the one offered by TekSavvy. Then it's a matter of being able to sell your service to prospective customers. You'll save yourself a lot of hurdles but I wouldn't expect such a venture to be extremely lucrative.