Complex sentence: Bean 1941, p.365 When Colonel James McCay the 2nd Brigade commander landed Maclagen convinced him to move his brigade to the south, and established his headquarters on the seaward slope of 400 Plateau (McCay's Hill).
Split into simpler sentences: Bean 1941, p.365 When Colonel James McCay the 2nd Brigade commander landed Maclagen convinced him of the need to move his brigade to the south. Moving south McCay established his headquarters on the seaward slope of 400 Plateau (McCay's Hill).