Complex sentence: Therefore, in January 1918, Sovnarkom decided that the Worker-Peasant Red Army had to consist of volunteers from "the most class conscious and organized elements of the toiling masses" That was the end of the Red Guards and the creation of the Red Army.
Split into simpler sentences: Therefore, in January 1918, Sovnarkom decided that the Worker-Peasant Red Army had to consist of volunteers from "the most class conscious and organized elements of the toiling masses". That spelled the end of the Red Guards and the creation of the Red Army.