Help needed, I want to make a new team

Hi all, this year i decided to play my asociation in PC (xbox for online play). I want to create a new team and take the place of one of the worst team in nba. I'm making a logo and i already got the idea for court and jersey, photoshop is not a problem, so i want to know how can i make this happen. Tools needed, maybe some tutorials, etc. Thanks in advance!!

Why in the world would you want to play an association mode just to be the worst team on purpose? I mean, what's the point?

I think i didn't explain good enought. I will make a new team (new logo, new court, etc) and take the spot of an existing team of the nba. But i dont know how can i do it, so i'm looking for some tutorials on editing the game to be able to do it.