Complex sentence: In the first Sikh war he was again in command of the cavalry at Battle of Sobraon on 10 Feb.1846, and led it in file over the intrenchments on the right, doing work (as Gough said) usually left to infantry and artillery.
Split into simpler sentences: In the First Anglo-Sikh War he was again in command of the cavalry at the Battle of Sobraon on 10 February 1846. He led the cavalry in file over the entrenchments on the right of the line, doing work (as Gough said) usually left to infantry and artillery.