Complex sentence: Khalid's basic plan was to inflict as heavy casualties on the Persians as possible, also, to meet as low resistance as possible along the route of his advance, his objective was to capture Hira.
Split into simpler sentences: Khalid's basic plan was to inflict as heavy casualties on the Persians as possible. Also, to meet as low resistance as possible along the route of his advance, his objective was to capture Hira.