I'm not sure of the grammatical order in this scentence

I have learned about" Sentence topic, Time, Location, Subject, Indirect object, Direct object, Verb"

"学校から私に家へ手紙を送った"

Is "家へ手紙を" describing a direct object or is it something else ?"

I haven't learned all the kanji yet in the scentence and only know some of them

This scentence is from the sakubi grammer guide: https://sakubi.neocities.org/#moving