This achievement is actually pretty easy. As you head down the street from your team practice facility in My Player mode the building you need to enter is on the left almost right across from the intersection where Foot Locker and the NBA store are. Enter the building and the game will give you the option to create a Pro-Am Team. Create the team name, city, colors, etc. and when you are finished hit B and your team will be created. No need to play a game to get this achievement