Complex sentence: That year, the squadron was occupied with the normal peacetime routine of individual and unit training, including a training cruise in the Baltic, followed by a voyage to Spain that lasted from 7 May to 10 June.
Split into simpler sentences: That year, the squadron was occupied with the normal peacetime routine of individual and unit training. This included a training cruise in the Baltic, followed by a voyage to Spain that lasted from 7 May to 10 June.