Please remove the chicken's innards before cooking.
Literal
Cook-do before [time-に] chicken [possessive-の] entrails [object-を] pull-out please.
~する前に (before doing X) is a key time-sequencing pattern. 臓物 (ぞうもつ, entrails/giblets) is a somewhat specialized word for internal organs used as food. 抜く (to pull out/extract) is the appropriate verb for removing things from inside something.