Here's the situation from last season.
Starting XI: De Gea, Young, Smalling, Lindelöf, Shaw, Herrera, Matic, Pogba, Lingard, Rashford, Martial
Second XI: Romero, Dalot, Bailly, Jones, Rojo, McTominay, Pereira, Fred, Mata, Lukaku, Sancez
We shouldn't have more than 22 senior players. This means Valencia, Darmian and Grant out.
Young, Smalling Matic and Lingard should be moved to the second XI. This means Rojo, Bailly, Pereira and Mata out.
We have bought James, which should mean Sanchez out.
And De Gea, Pogba, Herrera and Lukaku wants to go.
Situation next season:
Starting XI: New GK, New RB, New CB, Lindelöf, Shaw, New CM, New DM, New CM, New RW, Rashford, Martial
Second XI: Romero, Dalot, Smalling, Jones, Young, McTominay, Matic, Fred, Lingard, New CF, James
That's 12 out and 8 in this summer, which I think is needed.