Complex sentence: Canby awaited him there with 3,800 men of whom most were infantry and only 1,200 were seasoned soldiers, the remainder consisting of 2,000 New Mexican volunteers, 100 Colorado volunteers, and 500 militia.
Split into simpler sentences: Canby awaited him there with 3,800 men of whom most were infantry. The remainder consisted of 2,000 New Mexican volunteers, 100 Colorado volunteers, and 500 militia.