Complex sentence: At the time Lydnikov was in command of the 39th Army at the 3rd Belorussian Front and together with the 43rd Army of the 1st Baltic Front, under the command of Army general Beloborodov, made an attack operation against German forces.
Split into simpler sentences: At the time Lydnikov was in command of 39 Army at the 3rd Belorussian Front. Together with 43 Army of the 1st Baltic Front In command of Army general Beloborodov made an attack operation against German forces.