With Atushi’s sports day coming up he needs a family member to participate in the family events.  Will it be Mom with her sudden hip pain, Dad with his knee acting up, or Atsumi?
Yeah, so I'll have to prep the day before...
Sí, tendré que prepararlos un día antes.
Sí, tendré que prepararlo todo el día antes.
Sim, ai tenho que 
preparar um dia antes...