Complex sentence: The First World War Ottoman Turkish Army was modelled after the German Empire Army, with most of its members being conscripted for two years (infantry) or three years (artillery); for the next twenty-three years they served in the reserve.
Split into simpler sentences: The First World War Ottoman Turkish Army was modelled after the German Empire Army, most of its members being conscripted for two years (infantry) or three years (artillery). Then for the next twenty-three years they served in the reserve.