Complex sentence: Two companies (Company F, 1st Dragoon, and Company H, 3rd United States Infantry) were garrisoned at the fort, in total there were 93 men living inside the fort's walls.
Split into simpler sentences: Two companies (Company F, 1st Dragoon, and Company H, 3rd United States Infantry) were garrisoned at the fort. In total, there were 93 men living inside the fort's walls.