ثُمَّ إِذَا شَآءَ أَنشَرَهُۥ
Sentence structure
إِذَا is a future, non-jussive conditional time adverb. شَآءَ occurs in its annexed clause and أَنشَرَهُۥ is the non-jussive response.
Ayah summary
Then, whenever Allah wills, He will raise him to life again.
ثُمَّ — Then
Grammar: ثُمَّ is a conjunction.
إِذَا — when
Grammar: إِذَا is a time adverb.
شَآءَ — He wills
Grammar: third-person masculine singular perfect verb; it functions as the condition clause.
أَنشَرَهُۥ — He will resurrect him
Grammar: form IV third-person masculine singular perfect verb; it functions as the answer to the condition. Attached هُۥ is a third-person masculine singular pronoun functioning as the object.