It depends on your philosophy, if u like attack, u usually only need 3-4 defenders, 3-5 supports, and 3-4 attacking. If you have a very athletic and good back four, you can utilize a more control/offensive orriented midfield, where u dont really need a DMC, but rather creative once that can help you control the tempo wihtout making critical mistakes. But if you go defensive, you should have at least 5-7 defensive mentality dudes with 3 support and probably 1-2 attacking. Or you can use standard pitch and play balance, where a good DMC will be useful to fill in the gap between your d-line and your midfield.