I use this manual to organize information on how to play the 4-3-3 soccer formation. The numbers in 4-3-3 refer to 4 defenders, 3 midfielders and 3 forwards. Sometimes the goalie is listed in the formation, then it is called 1-4-3-3. It's the same formation as the 4-3-3 where the 1 for the goalie is assumed.
Some play the 4-3-3 with three flat lines of 4 defenders, 3 midfielders, and 3 forwards. This manual is not about that version of the 4-3-3. This is about the 4-3-3 with 3 midfielders in the center of the formation in a triangle surrounded by a circle of defenders and forwards.