Complex sentence: The album is the 57th edition of the (UK) "Now!" series.The album sold 334,345 units in the first week of sales, and at the time of release it was the fastest selling record of the 21st century.
Split into simpler sentences: The album is the 57th edition of the (UK) "Now!" series. It sold 334,345 units in the first week of sales, and at the time of release it was the fastest selling record of the 21st century.