Complex sentence: The Saturdays began work on their fifth overall release in late 2011, with first single "30 Days" released in May 2012 and would serve as the lead single from their upcoming fifth album.
Split into simpler sentences: The Saturdays began work on their fifth overall release in late 2011. The first single "30 Days" was released in May 2012 and serves as the lead single from their upcoming fifth album.