It is already added, attach button wasn`t working. I`ll continue my game, would be interested how this goes with another team(s).
Preseason put it 3 slots for faster fluidity, training either teamwork/attacking (both should be needed). Default tactics/average-high (don`t get players injured) alternating with ball controll/attacking. 4.5 star coaches.
You should assign opposition instructions to Asisstant if you don`t have time. It should just man mark/close down 1-2 threats when necessary, changing nothing almost in the default tactic settings