Complex sentence: Once he returns, he is appointed master of the Far Reaches; ss with the Lower House, he appoints Dame Primus (Now both parts 1 and 2 of the will) his steward, and returns home.
Split into simpler sentences: Once he returns, he is appointed master of the Far Reaches. As with the Lower House, he appoints Dame Primus (Now both parts 1 and 2 of the will) his steward, and returns home.